The Haemoglobinopathies

There are two main groups of structurally abnormal haemoglobins in human beings including the thalassaemias. The polymorphic haemoglobins comprise four abnormal haemoglobins (Hb) with high frequencies. The best known is the sickle-cell gene. The sickle-cell gene is found with a frequency of up to 20% in some East African tribes and is common throughout most of central and west Africa. The disease has a wide and irregular distribution and can also be found in the Indian subcontinent, South Arabia, Scicily, Greece and Turkey.

Heterozygotes for thalassaemia show high levels of A2, and the biochemical lesion of retardation of the synthesis of the beta-polypeptide haemoglobin chain. This form is widespread in the Mediterranean region including Greece, France and Turkey. It is also common in the middle east such as Israel, Iran and Iraq). It occurs in India, south east Africa as well as the East Indies. Thalassaemia H2’s occur in up to 20% of the afflicted in Sardinia and other parts of Italy. Typical thalassaemia H2 cases have elevated levels of H2 with up to 11% in southern Liberia.

Haemoglobin C shows H2’s in as many as 30% in some tribes in northern Ghana and the adjacent High Volta. Either side of these regions the incidence decreases and is restricted mainly to west Africa. Haemoglobin E is widespread in south east Asian countries. The frequency of H2′ is up to 35% in Cambodia, but may be an over-estimate. Both haemoglobin E and thalassaemia  are common in many south east Asian populations.

Lower frequencies are found with the borderline haemoglobin polymorphisms. Lower frequencies are found in certain populations. In India several populations show only 1 to 2% for HbD, which is also the level for Algeria. Three haemoglobin variants are found in the Punjab, the Gujerat and Cyprus. It is known that, using analysis of the peptides, that these D variants are distinct from one another. It is worth noting that haemoglobin K and N occur with a frequency of 0.5 to 2% in many tribes in west Africa. Among the Berbers of Algeria up to 13.7% of haemoglobin is similar to HbK. Another polymorphism is HbO or Buginese X where 1% of the Buginese tested in positive Sulawesi (formerly Celebes) but absent in others.

Abnormal foetal haemoglobins have been found that include Bart’s or gamma chains. There is the Alexandra type and the Augusta-1 which is entirely composed of beta-polypeptide chains. Abnormal foetal haemoglobins are widely distributed in tropical countries that include Africa, Singapore, and Greece. The Bart’s Hb and adult HbH are thought to be associated with a variant of thalassaemia (which consists entirely of beta-polypeptide chains that affect the alpha-chain. There are numerous Hb’s in still lower frequencies.

Derived from lecture notes at Oxford Polytechnic (1986).

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The ABO Blood Group System, Rhesus Incompatibility and Disease.

1. Genetics of the ABO Blood Groups.

The ABO system is under the control of three genes, all the alleles being at one locus. Two alleles control A, A1 and A2. The antibody of one serum is incompatible with the cell antigen of another blood. Thus A possesses antibody B, group B has antibody A, and group AB has no antibodies. Group O has antibodies A and B. The groups A and B are dominant whereas O is recessive. Two genes therefore control the blood group. No child can possess an ABO antigen that is not in the parents. The A group is sub-divided, anti-A containing two antibodies, and these are alpha and alpha-1. Therefore alpha-1 is not present in A2 or A2B. Possible groups therefore are: A1A1; A1A2; A1B; A2B; A1o, A2O, plus of course BB; BO, and OO.

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Table 1ABO Serum Agglutination Reactions.

2. Secretors and non-secretors. 

In the ABO system, in the red cells, antigens and agglutinogens are present in alcohol soluble form. In some individuals they occur in a water soluble form and are thus present in other body secretions and fluids. The fluids they have been detected in are saliva, semen, amniotic fluid, tears, gastric juice, urine, and sweat. Group A secretes A, group B secretes B, and group O secretes substance H. Secretor status in the UK is 78% secrete and 22% are non-secretors.

The secretion of antigens in water soluble form is due to gene S. Gene S has a recessive allele s. Thus homozygous SS or heterozygous Ss are all secretors. Homozygous ss are all non-secretors. The inheritance of the S gene is independent of the ABO system, therefore there is no linkage.

3. Geographical distribution.

Variation occurs but is continuous in form. There is some regional heterogeneity. The world distribution shows considerable variation. [Kopec: Distribution of ABO Blood Groups in the UK. OUP]. ABO is distinguishable in apes with chimps showing A and O, Orangs and Gibbons with A and B, and gorillas with near A and near B.

The ABO system was established early in human evolution and has been maintained ever since. The pattern of variability is consistent with genetic drift, due to spatial and temporal isolation of populations. Also random effects may have operated. This when selective effects have been excluded to allow the drift explanation. Selection effects include action against the heterozygotes in the form of Erythroblastosis foetalis or haemolytic disease of the newborn. Rhesus incompatibility between the mother and her foetus is expected to occur in about 9% of conceptions in Europeans. This is predicted on the basis of a frequency of Rh(-) female times Rh(+) male matings, and a relative frequency of homozygotes amongst Rh(+) fathers. Haemolytic disease of the newborn due to Rhesus incompatibility occurs in about 0.6% of European births. This is strongly associated between the incidence and parity with only about 5% of offspring with haemolythic disease being first born, some 40-50% of the first appearance in families occur at third or later births.

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Table 2. Geographical Variation for Blood Group Allele Frequencies.

4. Rhesus and ABO incompatibility.

ABO incompatibility between the foetus and its mother is expected to occur in some 20% of conceptions in Europeans. This is predicted from frequency of: O female x A male; O x B; O x AB; A x B; B x A; A x AB; and B x AB matings, with a relative frequency of homozygotes among A and B fathers. Only 4 to 13% of mothers with Rhesus haemolytic disease children are ABO incompatible with their offspring. This suggests ABO status protects against Rhesus incompatibility effects. Haemolytic disease due to ABO status alone occurs in about 0.1% of births in Europe. Incompatibility selection against heterozygotes in the absence of other balancing forces gives rise to an unstable equilibrium. When this equilibrium is unbalanced or disturbed the rarest of the polymorphic alleles will decline in frequency.

4.  Blood Groups and Disease susceptibility.

Group O show a preponderance towards peptic ulcers, and A towards stomach carcinomas. This is a statistical relationship. A also show a trend to thromboembolism. A association between infectious diseases and blood groups has also been considered. It is claimed that there exists an epidemiological relationship between some groups and plagues and smallpox.

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Table 3.  ABO and Secretor Polymorphisms and Disease Susceptibility.

5. Unlinked loci in the ABO system. 

Four other loci are involved in determining the specific antigenic specificity of the macromolecules of the ABO system, and these are H, Lewis (Le), Secretor (se) and ABO loci. Genes A and B can only modify the H-substance, and not its precursor. They are thus ineffective in the heterozygous hh. With regard to the soluble substances the H gene can probably only act in the presence of Se, and therefore ineffective in genetic sese.

Derived from lecture notes and course hand-outs at University of Oxford (1971-1974) and Oxford Polytechnic (1986).

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Age Determination in Infant and Child Skeletal Remains.

1.  Suture and fontanelle closure

The skull sutures estimates are unreliable due to too much variation. Suture closure begins on the inner surface and proceeds outwards to completion ten years later. Sutures are usually obliterated between 25 and 30 years of age. Partial obliteration for the sagittal suture is during the early 30’s, for the coronal suture it is during the 40’s, and the lamboidal during the 50’s.

Obliteration proceeds towards the bregma towards the medio-frontal and is complete by the 2nd year. Frontal suture is called metopism. A small supra-nasal portion is retained until the 6th year.

With regard to the fontanelle obliteration the sagittal or obelion is gone after the first two months of birth. The posterior or occipital apex fontanelle also seals two months after birth. For the antero-lateral or pterion the time scale is three months. The postero-lateral or parietal fontanelle disappears by the end of the first year followed by the bregmatic in the second year.

Fusion of the mandible two halves and symphysis is by the end of the second year.

2. Dental eruption

With regard to the milk dentition sex differences in dental maturation are slight. The approximate age of tooth eruption for deciduous or ‘milk teeth’ is as follows: lower central incisors is between 5 to 12 months; lower lateral incisors between 6 and 14 months; first molars between 13 to 20 months; the canines between 13 to 30 months; and the second molars between 18 to 38 months.

For the permanent dentition the first molars appear during the 6th year, the central incisors during the 7th, the lateral incisors during the 8th year, followed by the first premolars in the 9th. The second premolars appear in the 10th year followed by the canines from the 11th to 12th year. The second molars erupt during the 12th to 13th years with the third molars, or ‘wisdom teeth during the period 17th to 25th year.

The deciduous dental eruption of 20 teeth provides incisors 2/2; canines 1/1, and molars 2/2/. The permanent dentition of 32 teeth provides incisors 2/2, canines 1/1, premolars 2/2, and molars 3/3. Dental attrition relates to the eruption process in terms of years.

 

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Analytical Methods for Dating Human Bones.

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1. Introduction

An aging process is inherent in organic material. See Carbon 14 dating (Libby, W. F. 1947). After death the radioactive C14 is not replenished from the atmosphere. There occurs disintegration at a constant rate. The quantity is halved after 5,570 years which is the Libby Value. There is a practical limitation of radiocarbon dating because the certain minimum quantity of organic carbon must be available in the sample specimen.

Calcined bone is undateable, whereas charred bone is potentially dateable. The absolute age of a skull or mandible is usually obtained indirectly when it comes from a deposit containing more suitable for radiocarbon dating.

Contemporaneity is not always justifiable due to mankind’s long established practices of burying the dead. The relative age of a fossil bone is determined by comparison of the chemical composition with that of other fossil bones of known ages. Either from the same site or some other area if they have been preserved under comparable conditions. As soon as bones are buried their composition is subject to chemical changes, some of which are slow, some fairly rapid.

2. Buried organic matter.

Fats, protein (collagen) and the fatty composition are lost quite rapidly. The protein disappears much more slowly. Under some conditions, such as permanently frozen soil or exclusion of air and bacteria, the protein may persist for tens of thousands of years.

The appearance and texture of bone is not a reliable guide to how much organic matter it contains. The organic content of fossil bones has become widely regarded as an unreliable criterion for their antiquity. Some bones that appear to be well fossilised do in fact contain considerable amounts of protein. Relative ages can be determined by comparison of the contents that include nitrogen, carbon, and chemically bound water. Also the quantity of mineral ash after burning which increases with age. It is convenient to assess the residual organic matter in fossil bone or dentine by determination of the nitrogen content. As bone protein or collagen decays it becomes fossilised and broken down into amino-acids. These are leached out or retained according to local conditions.

3. Changes in mineral matter of buried bones.

This depends on the composition of the percolating ground water which is of two kinds. Alteration of the phosphatic material of which bones are mainly composed is hydroxyapatite. The addition of new mineral matter, such as lime or iron oxide, changes the latter and leads to an increase in weight. The most valuable change however is the irreversible substitution of one element for another in the hydroxyapatite. These two elements are thus fluorine and uranium.

The fluorine is distributed is soluble fluorides in trace quantities in all ground waters. Over the passage of time bones and teeth in permeable deposits progressively accumulate fluorine. The fluorine becomes fixed in the bone and is not readily removed which provides the fluorine dating method. With regard to uranium mineral phosphates, including bones, all contain uranium.

4. Dating fossil man.

dating fossil mankind requires correct placing in the Pleistocene and Holocene periods. Also the determination of morphological evidence in terms of the hominid phylogeny. Also the correct ecological information of the sites. Considerations of fossil age raises two questions. Firstly the relationship of geological, faunal, archaeological sequences at the site in terms of chronological age in years BP. Secondly, the remains have to have contemporaneity with deposits. The association of faunal, climatic and archaeological information derived from the site can be the same as the specimen.

This allows assessment of relative age and answers the second question or determination of absolute or chronometric age. To determine contemporaneity evidence is required to show there is no unnatural disturbance of the specimen, no intrusive burial, and no derivation from older deposits. This requires photographs in situ and stratigraphic drawings. Furthermore, two chemical tests are needed. Buried bone accumulates fluorine by a rate determined by local conditions. These include soil concentration and length of burial. This shows also contemporaneity of hominid bones and animal bones buried at the same site. Nitrogen  decreases in buried bone and affects nitrogen concentrations. Therefore nitrogen disappears rapidly under oxidising conditions and may be absent.

5. Relative and absolute dating.

With regard to relative dating Comparative geology includes correlations with soil pollen content. Studies of the fossil fauna assemblage, comparison with other sites, and the different layers at the same site. Also comparison and recognition of stone implements. This allows the establishment of the relative position of the specimen in the geological, climatic, faunal and archaeological sequence.

Absolute dating implies chronometry and is the oldest method in use. The upper atmosphere, nitrogen, and the bombard of cosmic radiation results in a known proportion of radioactive carbon which is incorporated into atmospheric carbon dioxide. The occurs absorption of CO2 by vegetation and thence by animal tissues. Burial of bones means Carbon14 begins to decay at a known rate. Mathematical translation of the C14 content of organic material gives an estimate of specimen age. In practice the Carbon14 technique is limited to specimens 60,000 to 70,000 years of age. This is because the C14 content is too small then to estimate.

Another radiometric method is the Potassium-Argon technique or K/Ar. Naturally occurring potassium (K) contains an isotope which decays at a constant rate and produces Argon. This argon is held within the crystals of some potassic compounds. Argon content estimation of deposits around the specimen will give the indirect estimation of the age of specimen. In practice the method is limited to 20,000 years of age specimens.

6. Cave sediments and prehistory.

Cave excavations demand not only knowledge of prehistory but also of geological observation and research. Caves are places of manifold geological occurrences and the preservation of sediments. The exact analysis of the sedimentary accumulation in a cave permits the deduction of the sequence, and the causes of geological events.

Nearly all caves and cave deposits date from the later Quartenary period and the Upper Pleistocene and Holocene. Mankind has frequented and used rock shelters at all times and in many areas. In these locations the lived, buried their dead, and used them as ritual sites.

7.  Sex determination in earlier humankind.

No single measurable character of any bone will serve by itself to distinguish two different individuals, either racially or sexually. Critical examination of the combination of all of the characters gives results of value.

Anthropologists, often confronted with the problem of sexing bone find the only practical way is accomplished by combining measurements. These are those obtained by combing morphological observations in a fashion as logically valid as possible. From a genetical point of view observation and measurement of characters is required.

If observations and measurements are in keeping with normal patterns of growth, morphology, and the function of bone, they may prove to be of value in sex determination. We are still far from understanding to what extent, genetic, environmental, hormonal, or other factors are responsible for the final shape of bone. It is not advisable to trust to a single, metrical or morphological character.

In earlier populations, as in modern ones, we have examples of varying sex ratios. For prehistoric groups the sex ratio, combined with differential fertility and mortality, can greatly modify the outward appearance of a population. It shows therefore that it is not uncommon to find unequal proportions between sexes. Factors constantly change sex ratio so that this changes from one age to another, one generation to another. It follows that what is found in one archaeological stratum may not serve as a pattern for any postulations about human remains found in adjacent strata, whether above of below.

Sexual dimorphism in prehistoric remains and various modern humans do not have the same degree of sexual dimorphism. The pronounced sexual differences in size is a primitive condition. Upper Palaeolithic populations in Europe are similar to their descendants. One cannot judge prehistoric remains by the same criteria as for modern ones.

8. Methods of sex determination.

It is impossible to base sex determination on one character alone. Neither metric of morphological. Masculine characteristics in one bone may be accompanied by female traits in another. This is equally true for prehistoric and modern remains. There are three areas to analyse: pelvis; skull and face; articular surfaces of joints and long bones.

Originally lecture and course notes dated 1972 and research preamble 1975-76.

 

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Michelangelo: sculpture and architecture for the Medici

1.  Introduction

Born at Caprese Michelangelo (1475-1564) came from a family of some social standing, his father being a Florentine official. After some parental opposition he was apprenticed to Ghirlandaio and trained in fresco painting and with whom he stayed briefly. It was, despite his architecture, painting and poetry, as a sculptor he wished to be known. Michelangelo told his biographer Condivi he was self-trained and there is some truth in the claim that he was autodidactic. It was in the Medici household that he became a sculptor.

The Medici family were prominent Florentine commercial figures with Cosimo (1389-1464) a foremost individual from 1434, a role intensified by his son Piero and grandson Lorenzo the Magnificent (1449-1492). Praised alternately as patrons and castigated as tyrants the Medici family were a commercial nobility and part of Florence’s group of powerful families called the popolani grassi (Eliot, 1996). Periods of exile from Florence (which profoundly affected Michelangelo’s career) between 1494 and 1512, and again from 1527 to 1530, were followers by their gaining near complete control of Tuscany as dukes and grand dukes (Hale, 1995), a process aided and abetted by the Medici popes Leo X (Giovanni de’ Medici, 1475­-1521 and pope 1513-21) and Clement VII (Giulio de’ Medici, 1478 to 1534, pope between 1523 and 1524).

Michelangelo went around Florence drawing from the frescoes of Giotto and Masaccio whereupon he stayed in the household of Lorenzo de’ Medici from 1490 until 1494, two years after Lorenzo’s death in 1492. Whilst in the Medici palace, where he studied under Benedetto di Giovanni (1420-91), Michelangelo would have encountered and had acess to such humanist and Neoplatonist scholars as Ficino, Landino, Poliziano, and Pico da Mirandola – from whom his interest in Neoplatonism derives. Art, for Michelangelo, was thus an intellectual activity. During this time he would also have listened to the sermons of Savonarola and read that friar’s writings. Two obsessions developed in this setting, against which Michelangelo measured his own achievement, the sculpture of Donatello and the ancients. After the death of Lorenzo he went to Bologna and thence to Rome.

The 1490’s were troubled years for the Medici and Florence. It was the era of Savonarola’s fiery scourges and when Michelangelo’s own republican sentiments were confirmed. During this period he strengthened his links with Lorenzo’s cousins Giovanni and Lorenzo di Pierfrancesco – later Popolano. It was the impending march of Charles VIII of France on Florence that forced Michelangelo to flee the house of Piero de’ Medici for Bologna in 1494. The role of the Medici and the other popolano grassi with regards to their patronisation of scholars and artists, as well as Michelangelo with his lesser noble background, can be summed up thus `…the house of Medici, the petty despots of many a small city-state and the rich bourgeoisie preferred to patronise an intelligentsia to some extent free# from religious obligations, and ready to recognise personal achievement independent of rank and birth.’ (Green, 1952). Michelangelo’s earliest carvings consist largely of imitations of the antique and are of a type he could only have learned in the sculpture garden of Lorenzo. (Clark, 1978).

2.0  Early sculpture in Lorenzo de’ Medici’s Florence

It was Ghirlandaio who formed the early talent of Michelangelo and it was in his studio that he came to the attention of Lorenzo de’ Medici (Cleugh, 1993). Presumably Ghirlandaio recognised the sculptural ability and ‘…arranged for him to enter Bertoldo’s school for sculptors in the Medici garden on the Piazza di S. Marco in 1489.’ (Von Einem, 1973, citing Vasari, and Tolnay, 1947). It was Ascanio Condivi, liDgrapher of Michelangelo, who records however that it was one Granacci who took him to the Medici garden (Frey, 1907), and that Lorenzo ‘…opened his garden as though it were a school or studio.’ (Von Einem, 1973). Thus the transfer to the sculpture garden allowed Michelangelo `…to attend the meetings of the Platonic Academy. He never forgot them, remaining a Christian Platonist till his death. This crucial period in the great artists development ended with Lorenzo’s death in 1492.’ (Cleugh, 1993).

Lorenzo de’ Medici is credited with being the first to recognise Michelangelo’s ability, whom he befriended and ‘…generously assigning him a room in his palace and a place at his table.’ (Schevill, 1963). It was Condivi again who recorded that Michelangelo’s copy of an antique faun (now lost) prompted Lorenzo to invite him to his palace (Olson, 1992). Bertoldo was Lorenzo’s keeper of the Medici fragments (4 antique sculpture on the Via Larga (Murray, 1995). Bertoldo, the former pupil of Donatello, was given the task by Lorenzo de’ Medici of `…assembling a body o first-class sculptors and painters and instructing them in the proper ways of art.’ (Von Einem, 1973, citing Gengaro, 1961). However, Herbert von Einem (1973) casts doubt on Vasari’s information concerning the role played by Bertoldo as Michelangelo’s teacher. Sources in the garden for his inspiration were the fragments and antique cameos (Murray, 1995), though Schevill (1963) avers that Michelangelo in the Medici garden was under `…no other guidance than his own unerring instinct…’ as he ‘…absorbed the Florentine tradition as manifested in its most rugged representatives, Giotto, Masaccio, Donatello, Pollaiuolo, and Signorelli.’

In 1490 Michelangelo was esconced as a house guest in Lorenzo’s palazzo where he lived with sons of Lorenzo – Piero (expelled by Charles VIII in 1494), Giovanni (later Pope Leo X), and Giuliano (whose tomb he later carved at Capella Medicea). At this time he became acquainted with Neoplatonism ‘…which played so important a part in his art and poetry.’ (Von Einem, 1973, Also citing Panofsky, 1939). Bertoldo died in 1491 and the young Michelangelo stayed on and appears to have been a familiar of the Medici household (Murray, 1995). During this period (prior to late 1492) he carved two pieces, presumably for Lorenzo, and these were his Madonna of the Stairs and Battle of the Centaurs.

2.1. The Madonna of the Stairs

Michelangelo’s earliest extant work when he was aged only sixteen. A relief, it is a devotional work, see Figure 1, and a popular fifteenth century form in the tradition of Donatello. Even so, this low relief work is `…an old motif – one uncommon, however in fifteenth century Florentine art…’ (Von Einem, 1973). It is a juvenile work in an early style that is heavily classically based but with Renaissance inspiration. It is carved from white Carara marble and is noted for its classical amoretti. Its implicit monumentality belies its small size. It is carved from a waxy and translucent slab, like alabaster, and reminiscent of Desidirio. It was a theme which Michelangelo was to `…develop in all its glory in his Madonna for the Medici Chapel.’ (Von Einem, 1973).

Stairs

Figure 1.  Michelangelo.  Madonna of the Stairs (1490-92). Marble. Source: Public domain.

Carved in rilievo schaccitto it represents Michelangelo’s exploration of quattrocento techniques. The ‘…brooding figure of the Virgin…(Murray, 1995, p24) can be compared with Donatello’s Pazzi Madonna of the 1420’s to 1430’s, see Figure 2, and with Michelangelo’s own later Pitti Tondo of 1504-1505, see Figure 3.

Pazzi

Figure 2.  Donatello.  Pazzi Madonna (1420-30’s).  Marble.  Source: Public domain.

It has the unusual aspect of Mary suckling Christ. The Madonna’s face is in classical profile and she sits on a square block – a studio prop for models and Michelangelo’s hallmark. He chose not to show the child’s face and places him in an odd position ­perhaps nursing or sleeping and foreshadowing his death. Christ is also encased in drapery which suggests protection, either shroud or womb.

Pitti

Figure 3.  Michelangelo.  Pitti Tondo (1504-05).  Marble.  Source: Public domain.

The novel stairs are possibly related to Girolamo Benevieni’s Scala della vita spirituale sopra it nome di Maria. Girolamo Benevieni (1453-1542) was a Florentine writer in the circle of Lorenzo de’ Medici, and composed lyrical and narrative verse. Girolamo sought to embody Ficino’s concept of Platonic love. Praised by Mirandola he eventually became (like Botticelli) a devotee of Savonarola. Analytically the Madonna of the Stairs contains classical elements of relief sculpture with themes derived from the humanist circle in which Michelangelo moved within Lorenzo’s household. In the background four youths handle a long cloth identified as a winding sheet or shroud. In essence this relief is closer to Donatello’s Pazzi Madonna, see Figure 2, than the intervening lyrical Madonnas of Rossellino and Desidirio.

2.2 The Battle of the Centaurs

This second early piece was also executed when Michelangelo was around sixteen. Carved in marble in 1491 or 1492, see Figure 4, it resembles Bertoldo’s bronze relief Battle (with Hercules) done some time after 1478, see Figure 5. The figures display vigorous attitudes and illustrate a Renaissance interest in the human body and form. The relief is thus a `…tightly knit mass of struggling nude figures…’ (Murray, 1995). Bertoldo’s Battle is based partly on a damaged Roman sarcophagus and is not a mere copy (Olson, 1992). The work is variously known as the Rape of Dejanira, the Battle of Hercules and Centaurs, and Battle of the Centaurs and Lapiths, that ‘…foreshadows not only the classical style of his Florentine period, but the anti-classical expressiveness of his later works.’ (Clark, 1978). Therefore if this work was ‘…probably for Lorenzo de’ Medici and left unfinished at his death…’ (Olson, 1992) it renews the concept of Pliny that an unfinished work was preferable because it revealed an artists method and thought processes.

628px-Michelangelo,_centauromachia,_1492_ca__01

Figure 4.  Michelangelo.  Battle of the Centaurs (1492).  Marble. Source: Public domain.

battle

Figure 5.  Bertoldo di Giovanni.  Battle (with Hercules). After 1478. Bronze. Source: Public Domain.

The Battle relief embodies the dictum of Pythagoras that ‘Man is the measure of all things’, which was echoed by Alberti and became a tenet of the Renaissance. The whole relief is conceived in terms of the body as an expressive vehicle, as much as it reflects Michelangelo’s ‘…study of late Roman sarcophagi, Bertoldo, the Pisani and Pollaiuolo.’ (Olson, 1992). Moreover, the relief of the Battle of the Centaurs was made ‘…at the suggestion of Poliziano who explained the whole myth to him from beginning to end.’ (Burke, 1987, cites also Condivi, 1964). At this time Michelangelo was experimenting with the deeply undercut style of Roman sarcophagi and quite different from Donatello’s very shallow relief. Both the Madonna of the Stairs and the Battle of the Centaurs show the ‘…squareness, the monumentality, the restlessness, the search for the union of many planes.’ (Stokes, 1955). Again, both reliefs are unique and even anticipate the future work of Michelangelo in the sense that the `…Madonna of the Stairs points forward to the Madonna in the Medici Chapel, and the Battle of the Centaurs to the Battle of Cascina, the Flood and even the Last Judgement.’ (Von Einem, 1973).

3.0 Michelangelo and the Medici Pope Leo X

The death of Lorenzo de’ Medici combined with the expulsion of the Medici from Florence in 1494, not to mention the ascendancy of Savonarola’s power conspired to bring Michelangelo’s ‘…incipient patronage to a brusque conclusion.’ (Murray, 1995). Michelangelo was not happy in the house of Piero de’ Medici and in October 1494 ‘…there ocurred the first of those panic flights which were to be repeated three times in the course of his life.’ (Clark, 1978). The advance of the French army to the gates of Florence may have forced Michelangelo to feel himself ‘…compromised by his Medici associations, prudently removed to Venice, and then, closer at hand, to Bologna.’ (Murray, 1995). According to Von Einem (1973) Michelangelo’s sudden decampment from Florence ‘…reveals for the first time…’ his ‘…impulsive nature, which asserts itself not only over his personal courage but also over any feeling of gratitude towards his patrons.’

Leo X, son of Lorenzo, was the first Medici pope, who allowed his brother Giuliano, Duke of Nemours to follow him to Rome (Schevill, 1963), and who died in 1516. Leo X made a client of Michelangelo the ‘…surly young sculptor…’ 1993) and employed him for the ill-fated S. Lorenzo facade. Leo X reputedly said of Michelangelo that ‘He is terrifying, one can’t get on with him.’ (Stokes, 1955,  citing Gaye, 1839-40), whereas even Sebastiano del Piombo wrote to Michelangelo that ‘…you frighten everyone, even Popes.’ (Stokes, 1955, citing Le Pileur, 1890). And yet Clement VII, the great admirer of Michelangelo ‘…treated him with the respect that he would ordinarily have accorded a sovereign prince.’ (Cleugh, 1993).

3.1 The facade of San Lorenzo

Michelangelo arrived in Rome in the summer of 1496 with a letter of introduction from Lorenzo di Pierfrancesco de’ Medici, the pupil of Ficino and friend of Botticelli (Clark, 1978). Republican rule was restored in Florence between 1495 and 1496 so Michelangelo returned from Rome in 1501. He then carved a St John the Baptist (now lost) for Lorenzo Pierfrancesco (Olson, 1992) which reputedly was ‘…a marble statue of St John as a young man…’ (Von Einem, 1973). He was then recalled to Rome by Pope Julius II in 1505. The earliest example of architecture by Michelangelo was the 1505 lower storey of the Julius II tomb plus a structural design for the Sistine ceiling. However, in 1515 it was proposed that the Medici church in Florence – Brunelleschi’s new San Lorenzo – should have its facade completed. This project was proposed by Pope Leo X and Michelangelo began work in 1516, the contract signed in 1518, see Figure 6, with a design of an architectural frame filled with sculpture (Murray, 1995). Leo X had visited Florence in 1515 who, as Giovanni de’ Medici, Michelangelo had grown up with in Lorenzo’s house. Moreover it also ‘…seems to have been Giuliano da Sangallo who aroused the interest of the new pope Leo X de Medici…in this idea.’ (Von Einem, 1973).

S Lorenzo

Figure 6.  Michelangelo. Model of S. Lorenzo façade (1516). Source: Public domain.

Pope Leo X (1513-1521) did not employ Michelangelo as a painter, nor a sculptor, but as an architect, having designed for Leo the front of a small chapel in Castel Sant’Angelo in Rome. A chapel, not suprisingly, dedicated to the patron saints of the Medici family – Cosmas and Damian. Also Leo decided to transform the open ground floor of the loggia of the Medici Palace in Florence. Again, Michelangelo was entrusted with building the facade.

Regarding the facade Leo X was unable to get Michelangelo to cooperate with his other nominee, Baccio d’Agnoli, so by 1517 Michelangelo was in sole charge of the facade of S. Lorenzo. The facade came to nothing, a plan that envisaged a large number of statues, and which ran into problems concerning marble procurement, eventually faded. Concerning the statues Cardinal Giulio de’ Medici (the future Clement VII) decided on the identity of most of the figures and these included: St Laurence; John the Baptist; Peter; Paul; Cosmas; Damian; the four evangelists; legend of St Laurence reliefs; Peter’s crucifixion; and the conversion of St Paul. (Von Einem, 1973).

4.0 Michelangelo and the Medici pope Clement VII

In 1523 Cardinal Giulio de’ Medici became pope Clement VII and commissioned Michelangelo to create a sacrarium or reliquary loggia for the Pergamo of S. Lorenzo, and which was to store the accumulated relics of Lorenzo de’ Medici. Designed in 1526 it was completed between 1532 and 1533. Moreover, Clement VII commissioned the Last Judgement for the altar wall in the Sistine Chapel.

The idea of the Medici Chapel, as a family funerary chapel, was first mooted by Leo X in 1519 and this New Sacristy (Nuovo Sagrestia) in Florence Michelangelo’s greatest ensemble.’ (Olson, 1992), indeed one of his outstanding masterpieces (Cleugh, 1993). Six tombs were planned for Lorenzo the Magnificent, Giuliano de’ Medici (brother of Lorenzo), Leo X, Clement VII, and two never completed for the younger Giuliano, and Lorenzo di Piero. At the instigation of Cardinal Giulio de’ Medici Leo X decided to erect this family mausoleum and the final design was handed to Giulio in 1520 (Frey, 1899), but the tombs for Leo X and Clement VII were never completed (Tolnay, 1947). Even still, Michelangelo abandoned the work in 1534 despite it being his oldest completed building (Von Einem, 1973). Delayed until the death of Leo X work proceeded in 1523 under Clement VII (illegitimate son of Giuliano de’ Medici) and commemorated four Medici: Lorenzo and his brother Giuliano; Giuliano, Duke of Nemours (d.1516); and Lorenzo, Duke of Urbino who died in 1519 (Olson, 1992).

4.1 The Medici Chapel

The New Sacristy is of small central plan with a domed choir at the end, see Figure 7, and comprises a system of pietra serena pilasters, entablatures and pedimented windows, all surmounted by a hemispherical dome in coffered all’antica style (Murray, 1995). Various architectural elements were classically inspired and by not using past formsand creating new ones Michelangelo shows detail and in the combination they are completely original.’ (Murray, 1995). In this sense the `…architecture and sculpture act one upon the other…’ as a ‘…single indivisible work.’ (Von Einem, 1973).

Medici chapel

Figure 7.  Michelangelo.  Medici Chapel, S. Lorenzo.  Source: Public domain.

The wall facing the altar contains sculptures of saints Cosmas and Damian flanking the Madonna and Child, the so-called Medici Madonna (Murray, 1995), but Cosmas and Damian were carved by Montesorli and Rafaello da Montelupo (after Michelangelo models) and it was only after some time that Vasari completed floor and walls (Von Einem, 1973). In deep niches over the sarcophagi are idealised portrait sculptures depicting Lorenzo as the Contemplative Life, Figure 8,

Tomb of guiliano

Figure 8. Tomb of Lorenzo de Medici.  Source: Public domain.

and Giuliano as the Active Life, see Figure 9, with both men in classical armour, with Lorenzo `…relaxed and thoughtful…’ and Giuliano’s ‘…alert pose of arrested movement.’ (Murray, 1995).

  guiliano

Figure 9Tomb of Guiliano de Medici.  Source: Public domain.

Lorenzo, see Figure 10, and Giuliano, see Figure 11, face each other from their recesses, the architectural function ‘…merely to serve as a backdrop to the statues…’ (Cleugh, 1993). There is no attempt to reproduce the actual features of the two dukes (Nemours, and Urbino).

Lorenzo tomb

Figure 10Figure of Lorenzo de Medici. Medici Chapel, S. Lorenzo.  Source: Public domain.

guilian tomb

Figure 11. Figure of Giuliano de Medici, S, Lorenzo.  Source: Public domain.

On each sarcophagus repose figures representing the times of the day, the `…positive times of Night and Day for the Active Life; the more indecisive times of Dawn and Dusk for the Contemplative Life.’ (Murray, 1995). Each sarcophagus carries two reclining nudes, one male, one female (though somewhat androgynous). These nudes represent Twilight or Evening, see Figure 12, and Dawn, see Figure 13, for Lorenzo, with Night, see Figure 14, and Day, see Figure 15, for Giuliano.

crepusculo

Figure 12Evening/crespuculo.  Tomb of Lorenzo de Medici.  Source: Public domain.

dawn

Figure 13Dawn/Aurora.  Tomb of Lorenzo de Medici.  Source: Public domain.

night

Figure 14Night/Notte.  Tomb of Giuliano de Medici.  Source: Public domain.

day

Figure 15.  Day/Giorno.  Tomb of Giuliano de Medici.  Source: Public domain.

In the recess of the chapel entrance wall, opposite the altar, stands the Medici Madonna, see Figure 16, flanked by the Medici patron saints (Stokes, 1955). A compact group, they lean forward and shelter the infant, stalwart old men resembling ancient sages with troubled faces that lend themselves to the image of the

madonna and child

Figure 16.  The Medici Madonna.  Source: Public domain.

whole chapel which ‘…silent and enclosed, expresses, in a blend of Christian and Platonic thought, the idea of the House of the Dead.’ (Murray, 1995). In the chapel there is now interaction between sculpture and architecture, the High Renaissance, like the mausoleum occupants, is no more.

4.2 The Laurentian Library

Lorenzo de’ Medici bequethed his library to Florence with the original intention that it be housed in the Monastery of S. Lorenzo. In 1524 Clement VII made provision for a modest project with normal windows which meant Michelangelo  had to heighten the structure (Murray, 1995). In 1557 Michelangelo delivererd a clay model for the Biblioteca Laurentiana, see Figure 17, that was eventually executed in 1560 by Ammanati (Wundrum, 1988). The central room is noted for a huge flight of freestandiniteps [see Figure 18] posessing three flights separated by balustrades `…so that they appear to be flowing like molten stone down from the library and spreading across the floorl’ (Murray, 1995). Vasari and Ammanati completed the steps based on Michelangelo’s sketches of 1550.

5.0 Summary and conclusion

Following the restoration of Medici power in Florence Michelangelo was eventually entrusted with completing the facade of S. Lorenzo, and embarking on the Medici funerary chapel (Kempers, 1987, citing also Langedijk, 1981). Michelangelo spent three periods in Florence, 1520-21, 1523-27, and 1530-34, working on the Medici Chapel (Stokes, 1955), as well as the adjoining Laurentian Library. The four completed tombs in the chapel are `…regarded as the crown of Renaissance sc ulpture, as the Sistine Chapel – executed by Michelangelo for Julius II – is considered to be that of Renaissance painting.’ (Cleugh, 1993). With regard to the facade of S. Lorenzo (never completed) the elevation designs were `…his first steps away from the classical world of the High Renaissance and towards the anti-classical world of Mannerism.’ (Von Einem, 1973).

There are two essential aspects of the work of Michelangelo, firstly his passion for anatomy, secondly his awareness of sin, thus his career began at a time `…when Graeco-Roman sculpture was a new and compelling discovery accepted by artists and patrons alike as an ultimate model.’ (Clark, 1978). However, in the process of his development Michelangelo demonstrated the `…inexhaustible repertoire of his movement studies which he used as a means of heightening expression…’ (Burke, 1987). It is this that forms one the bases of Mannerist sculpture. The relationship with Leo X showed the pope’s `…little understanding of Michelangelo’s greatness…’ (Cleugh, 1993) preferring to encourage and reward Raphael whilst also having little respect for Leonardo.

For Leo X Michelangelo devoted fifteen years of his life on the Medici Chapel. Years which were of great importance for Michelangelo’s development, time as an artist which embraces his change `…from the High Renaissance to Mannerism, and prepares the way for his later style.’ (Von Einem, 1973). In this sense a feature of Michelangelo’s sculpture was its idealisation and, as the figures of Lorenzo and Giuliano show, he was not really a portrait sculptor. It can be said that the Medici Chapel was the birthplace of Mannerism (manera = good manners)  defining a breaking of the classicist rules of order and harmony and a reaction therefore against the High Renaissance. The figures increasingly lose their individuality, show unnatural movements, and seem imbued with a melancholy presence (Von Einem, 1973).

Analytically, is the Medici Chapel inspired by the ideals of Neoplatonism? There are a number of motifs that enable such an interpretation: river gods and times of the day are found in antiquity – being known from reliefs on the Arch of Constantine in Rome; the contrast of figures as vita contemplativa and vita activa (Panofsky, 1939). If however Michelangelo has left the High Renaissance behind in the chapel then Von Einem’s view (1973) means it is `…unlikely that Michelangelo would have based his design for a chapel dedicated to the Resurrection on the ideas of Neoplatonism.’ The chapel, despite its motifs, is deeply Christian in sentiment, and in keeping with the beliefs of his ecclesiastical patron, pope Leo X. But then, Leo X was also a humanist and well versed classicist. Michelangelo had changed, at this juncture the twisted forms of antique sculpture, for example the Laocoon, and created an instrument `…to visualise the spiritual turmoil of the 16th century.’ (Clark, 1978). Michelangelo presaged therefore the demands of the Counter-Reformation.

Finally, Michelangelo’s personal turmoil interacted with the turmoil of his times (as indeed did Botticelli’s) and his development occurred despite the viscitudes of his patrons whose demands so often (e.g., Julius II’s tomb and Sistine ceiling) vitiated against Michelangelo’s demands on himself. Just as the awesome power of Michelangelo, his terribilita, brought conflicts with his patrons it also imbued his work with his own sense of worth, the individual worth of the increasingly independent minded artist. It remains a moot point whether he would have completed more projects had his patrons left him alone to actually do what they commissioned him to do, and he wanted to do for them.

For the Medici family Michelangelo was not a painter – for them he was a sculptor and architect, their personal monumentalist. It was not until Clement VII commissioned the Last Judgement did the Medici demand such skills, and even then the death of Clement VII transferred the altar wall’s commission to the behest of the next pope Paul III.

6.0 References

Burke, P. 1987. The Italian Renaissance. Polity Press.

Clark, K. 1978. The Young Michelangelo, in The Penguin Book of the Renaissance.  J.H.Plumb (ed).

Cleugh, J. 1993. Medici. The Barnes & Noble, NY.

Condivi, A. 1964. Vita di Michelangelo Buonarrotti. Barelli, E.S. (ed). Milan.

Eliot, G. 1996. Romola. Penguin, Harmondsworth.

Frey, K. 1899. Sammlung ausgewahiter Brief an Michelangelo Buonarrotti.  Berlin.

Frey, K. 1907. Micheiangiolo Bounarrotti. Vol. 1. Berlin.

Gaye, G. 1839. Carteggio inedito d’artista dei secoli XIV, XV, XVI. Florence, 1839‑40. Vol II. 489.

Gengaro, M.L. 1961. Maestro e Scolare, Bertoldo di Giovanni e Michelangelo. Commentari. Vol 12.

Green, V.H.H. 1952. Renaissance and Reformation. Edward Arnold, London.

Hale, J.R. 1995. Dictionary of the Renaissance. Thames & Hudson, London.

Kempers, B. 1987. Painting, Power, and Patronage. Penguin.

Langedijk, K. 1981. The Portraits of the Medici, 15th-18th Centuries. Florence. Vols 1-2.

Le Pileur, A. 1890. Les Correspondents de Michelangelo. Paris, p21.

Murray, L. 1995. The High Renaissance and Mannerism. Thames & Hudson, London.

Murray, P. 1996. Architecture of the Italian Renaissance. Thames & Hudson, London.

Olson, R. 1992. Italian Renaissance Sculpture. Thames & Hudson, London.

Panofsky, E. 1939. The Neoplatonic Movement and Michelangelo: Studies in Iconology. NY.

Schevill, F. 1963. Medieval and Renaissance Florence. Vol 2: The Coming of

Humanism and the Age of the Medici. Harper, NY.

Stokes, A. 1955. Michelangelo. Tavistock, London.

Tolnay, C, de. 1947. Michelangelo. Vol 1. Youth. Princeton, 2nd ed.

Vasari. Lives of the Artists.

Von Einem, H.Michelangelo. Methuen, London.

Wundrum, M. 1988. The Renaissance. Herbert Press, London.

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