Tetrabiblos

Overview and influence

Ptolemy is referred to as "the most famous of Greek astrologers" and "a pro-astrological authority of the highest magnitude". As a source of reference his Tetrabiblos is described as having "enjoyed almost the authority of a Bible among the astrological writers of a thousand years or more". Compiled in Alexandria in the 2nd century, the work gathered commentaries about it from its first publication. It was translated into Arabic in the 9th century, and is described as "by far the most influential source of medieval Islamic astrology".

With the translation of the Tetrabiblos into Latin in the 12th century, "Ptolemaic astrology" became integrated by Albertus Magnus and Thomas Aquinas into medieval Christian doctrine. This theological acceptance encouraged the teaching of Ptolemaic astrology in universities, often linked to medical studies. This, in turn, brought attention in literary works, such as Dante's, which helped shape the moral, religious and cosmological paradigm of Western Europe during the Medieval era. The Tetrabiblos was largely responsible for laying down the basic precepts of Renaissance astrology, and was a necessary textbook in some of the finest universities of Renaissance and early modern Europe.

Ptolemaic astrology continued to be taught at European universities into the 17th century, but by the mid-17th century the study struggled to maintain its position as one of the respected Liberal sciences. During this period, the contents of the Tetrabiblos faced severe theological condemnation. Antonio Merenda, a 17th-century professor of civil law at Pavia, dismissed the work as "a diabolical art of divination," writing that "no superstitious art is more fitted to forward the aims of the devil than the astrology of Ptolemy."

The intellectual standing of astrology collapsed rapidly at the end of the 17th century, but the historical impact of the Tetrabiblos upon world culture continues to engage the attention of scholars of classical philosophy and the history of sciences in antiquity. It also maintains its position as an influential textbook for practitioners of modern western astrology, and English translations of the text were published by astrologers in the 18th, 19th and 20th centuries. The early 20th-century Humanist astrologer Dane Rudhyar reported that the astrology of his era "originated almost entirely in the work of the Alexandrian astrologer, Claudius Ptolemy". Even 21st-century astrological textbooks have described the Tetrabiblos as being "without a doubt, indispensable for any serious student of astrology".

Title and date of composition

The commonly known Greek and Latin titles (Tetrabiblos and Quadripartitum respectively), meaning 'four books', are traditional nicknames for a work which in some Greek manuscripts is entitled Μαθηματικὴ τετράβιβλος σύνταξις, 'Mathematical treatise in four books'. Frank Eggleston Robbins, editor of the Loeb English translation published in 1940, considered it likely that this was the title used by Ptolemy himself, although he acknowledged that many other Greek manuscripts use the title Τὰ πρὸς Σύρον ἀποτελεσματικά, 'The prognostics addressed to Syrus'. An ancient anonymous commentary on the work states that some considered the term Tetrabiblos to be a fictitious name.

Hübner, editor of the 1998 Teubner Greek edition, uses the title Apotelesmatiká (biblía), '(books on) effects', which has been followed by recent scholars. Alexander Jones, editor of the Springer publication Ptolemy in Perspective (2010), considers that Ptolemy's own title remains unknown, but agrees that the term Apotelesmatika is "a credible guess". This term is variously translated to mean 'influences', 'effects' or 'prognostics'; reflecting the theme of work, which is concerned with gaining foreknowledge of the effects of predictable astronomical cycles.

There is no firmly established date for the compilation of the Tetrabiblos, but Ptolemy discloses in his 'Introductory Address' that he wrote his astrological treatise after completing his astronomical one: the Almagest. Evidence within the Almagest reveals that the astronomical work could not have been completed before about 145 AD, which demonstrates that Ptolemy wrote the Tetrabiblos towards the end of his life, sometime between completing the Almagest and his death, generally reported to be around 168 A.D.

Book I: principles and techniques

Opening chapters

The text begins with Ptolemy's address to "Syrus", an unidentified character to whom all Ptolemy's works are dedicated. In this Ptolemy differentiates between two types of astronomical study: the first (astronomy proper) which discovers the astronomical cycles and movements; the second (astrology) which investigates the changes these movements bring about. He states that each has its own science and the former is desirable in its own right "even though it does not attain the result given by its combination with the second". This is taken to demonstrate Ptolemy's view that astronomy and astrology are complementary studies, so that whilst astrology is less self-sufficient and factual, its employment makes the practice of astronomy more useful. Although the terms astronomia and astrologia were used interchangeably in ancient texts, this also demonstrates the early definition of two differentiated subjects which were discussed at length by Ptolemy in two separate works.

Ptolemy states that having dealt with the former subject (astronomy) in its own treatise, he "shall now give an account of the second and less self-sufficient method in a properly philosophical way, so that one whose aim is the truth might never compare its perceptions with the sureness of the first". In this, and further introductory remarks, he reveals his view that astrological prediction is extremely difficult and easily subject to error, but satisfactorily attainable to those who possess the necessary skill and experience, and of too much benefit to be dismissed simply because it can sometimes be mistaken.

Chapters 2 and 3 are important for giving Ptolemy's philosophical defense of his subject. Franz Boll noticed the arguments were paralleled in older sources, particularly those of the Stoic philosopher Posidonius (c.135 BCE–c.AD 51 BCE). Equally, Ptolemy's narrative was drawn upon by later philosophers and astronomers, such as Johannes Kepler, who used similar examples and the same order of arguments to explain the physical foundation of some astrological claims. Described as "scientifically speaking, perfectly laudable" by one modern commentator, another has condemned these chapters as the place where Ptolemy's "knowledge, intelligence and rhetorical skill" are most "misused".

In chapter one Ptolemy asserts the legitimacy of the study and identifies the two main arguments set against it:

the complexity of the subject makes its claim of providing reliable foreknowledge unattainable;

Introduction of principles

One of the unique features of the Tetrabiblos, amongst the astrological texts of its period, is the extent to which the first book not only introduces the basic astrological principles, but synthesises and explains the reasoning behind their reported associations in line with Aristotelian philosophy. Chapter four, for example, explains the "power of the planets" through their associations with the creative humoral qualities of warmth or moisture, or the reductive qualities of cold and dryness. Hence Mars is described as a destructive planet because its humoral association is excessive dryness, whilst Jupiter is defined as temperate and fertilising because its association is moderate warmth and humidity. These associations are based on the arrangements of the planets with regard to the Sun, as perceived from the geocentric perspective, by which their orbits are measured is if they are centred upon the Earth.

Uniting these Aristotelian principles with a prevalent Greek philosophy employed by Zeno of Citium and the Pythagoreans, the next three chapters arrange the planets into pairs of opposites. They may be benefic (moderately warming or moistening) or malefic (excessively cooling or drying); masculine (drying) or feminine (moistening); active and diurnal (suited to the qualities of the day and aligned with the nature of the Sun) or passive and nocturnal (suited to the qualities of the night and aligned with the nature of the Moon). Since these humoral associations derive from configurations with the Sun, chapter eight describes how they are subtly modified according to the phase of each planet's synodic cycle with the Sun.

Chapter nine discusses the "power of the fixed stars". Here, rather than give direct humoral associations, Ptolemy describes their "temperatures" as being like that of the planets he has already defined. Hence Aldebaran ("called the Torch") is described as having "a temperature like that of Mars", whilst other stars in the Hyades are "like that of Saturn and moderately like that of Mercury". At the end of the chapter Ptolemy clarifies that these are not his proposals, but are drawn from historical sources, being "the observations of the effects of the stars themselves as made by our predecessors".

Chapter ten returns to the humoral theme more explicitly, clarifying that the zodiac is aligned to the seasons and so expressive of the shifting emphasis through moisture, warmth, dryness and cold, (as brought about by spring, summer, autumn, and winter). Similarly, the four angles of the chart present an humoral emphasis through association with the effects of the four cardinal winds that blow from their aligned directions. The remainder of book one (up to the final two chapters which concern the planetary phases and aspectual applications), presents the rulerships, divisions, and configurations of the zodiac signs, most of which are related to astronomical definitions, seasonal effects, physics and geometry. Geometrical principles are used to define the favourable or unfavourable quality of astrological aspects, based on the angular relationship of planets and signs with ecliptic degrees.

Book II: Mundane astrology

Book II presents Ptolemy's treatise on mundane astrology. This offers a comprehensive review of ethnic stereotypes, eclipses, significations of comets and seasonal lunations, as used in the prediction of national economics, wars, epidemics, natural disasters and weather patterns. No other surviving ancient text offers a comparable account of this topic, in terms of the breadth and depth of detail offered by Ptolemy. Although no demonstrated examples are given, he writes with authority in this branch of his subject, which suggests it was of particular interest to him. Modern commentators have remarked that Ptolemy was "consciously taking a different approach" to contrast "with the 'old', infinitely complicated methods".

Ptolemy begins by stating he has briefly reviewed the important principles and will now develop the details of astrology in the appropriate order. His point is that astrological assessment of any 'particular' individual must rest upon prior knowledge of the 'general' temperament of their ethnic type; and that the circumstances of individual lives are subsumed, to some extent, within the fate of their community.

The second chapter gives a broad generalisation of how differences in physical traits occur between the inhabitants of the various climes (a demarcation based on latitude). Communities that live close to the equator, for example, are described as having black skins, small statures, and thick woolly hair, as a protective response to the burning heat of that location. By contrast, communities that have settled in high northern regions are defined by their colder environment and its greater share of moisture. Their bodily forms are paler, taller, with finer hair, and in their characteristics they are described as "somewhat cold in nature". Both types are described as lacking civilisation because of the extremes of their environment, whereas communities that live in temperate regions are medium in colouring, moderate in stature and enjoy a more equable lifestyle. The several regions are similarly defined according to the mix that arises within this kind of analysis. Ptolemy explains that such considerations are only dealt with summarily, as a background consideration for what follows. He also makes clear that such traits are to be found "generally present, but not in every individual".

In chapter 3 Ptolemy unites his interests in astrology and geography, to outline the astrological associations of "our inhabited world". Maps based on Ptolemy's Geographica show Ptolemy's definition of the inhabited world as (roughly) extending from the equator to latitude 66°N, covering the land mass between the Atlantic Ocean and East China Sea. Ptolemy extends the logic given in ancient Babylonian texts where the four quarters of the known world are attributed to the four triplicity arrangements of the zodiac. The attribution is based on association between the planets that govern the triplicities and the directions and winds those planets are affiliated with. For example, the 'Aries triplicity' (which includes Aries, Leo and Sagittarius) is chiefly dominated by Jupiter and assisted by Mars. Jupiter rules the north wind and Mars the west wind; therefore this triplicity governs the north-west quarter of Ptolemy's "inhabited world": the area known as Europe.

Use of eclipses

The remainder of the book shows how this information is used in the prediction of mundane events. Focus is given to eclipses, as the "first and most potent" cause of change, supplemented by examination of the 'stations' of the superior planets: Saturn, Jupiter and Mars. Although eclipses are deemed relevant to any nation affiliated with the zodiac signs in which they occur, Ptolemy's scrutiny is reserved for regions where they are visible, which he argues will manifest the effects most noticeably. The period of obscuration determines the endurance of the effect, with each hour proportioning to years for a solar eclipse and months for a lunar eclipse. The location of the eclipse with relation to the horizon is then used to judge whether the effects are most prevalent at the beginning, middle or end of the period, with times of intensification identified by planetary contacts to the degree of the eclipse which occur within this period.

Chapter 7 begins the examination of what type of event will manifest. This is judged by the angle of the horizon which precedes the eclipse in the chart set for the location under scrutiny and the planet(s) that dominate this angle by rulership and powerful aspectual connections. Whether the predicted effect is beneficial or destructive depends on the condition of these planets, whilst the type of manifestation is judged by the zodiac signs, fixed stars and constellations involved. The resulting prediction is of relevance to nations, but Ptolemy points out that certain individuals are more resonant to the effects than others; namely those have the Sun or Moon in their horoscopes in the same degree as the eclipse, or the degree that directly opposes it.

Within his Almagest Ptolemy explains that he had access to eclipse records kept for 900 years since the beginning of the reign of king Nabonassar (747 BC). In chapter 9 of the Tetrabiblos he shows knowledge of the Babylonian lore that accompanied these records in detailing the omens based on visual phenomena. The colours of eclipses and "the formations that occur near them, such as rods, halos, and the like" are considered along with the astrological significance of comets, in whether they take the form of "'beams', 'trumpets', 'jars', and the like". Meaning is derived from their position relative to the Sun and assessment of "the parts of the zodiac in which their heads appear and through the directions in which the shapes of their tails point". It is noted that here Ptolemy uses principles that fall outside the neat theoretical logic he presents in book I, being explicable only in terms of the mythological and omen tradition inherited from his ancient sources. He also defends the subjective nature of the analysis involved, asserting that it would be impossible to mention the proper outcome of all this investigation, which calls for enterprise and ingenuity from the astrologer creating the judgement.

Book III: Individual horoscopes (genetic influences and predispositions)

Books III and IV explore what Ptolemy terms "the genethlialogical art": the interpretation of a horoscope set for the moment of the birth of an individual. He explains that there are several cycles of life to consider but the starting point for all investigation is the time of conception or birth. The former "the genesis of the seed"” allows knowledge of events that precede the birth; the latter "the genesis of the man" is "more perfect in potentiality" because when the child leaves the womb and comes "forth into the light under the appropriate conformation of the heavens" the temperament, disposition and physical form of the body is set. The two moments are described as being linked by a "very similar causative power", so that the seed of the conception takes independent form at an astrologically suitable moment, whereby the impulse to give birth occurs under a "configuration of similar type to that which governed the child's formation in detail in the first place". Chapter 2 continues this theme in discussing the importance of calculating the precise degree of the ascendant at birth, the difficulty of recording local time precisely enough to establish this, and the methods available for rectification (i.e., ensuring the chart is correct).

Chapter 3 describes how the analysis of the chart is divided into predictions of:

essential, genetic qualities established prior to birth (such family and parental influences),

those that become known at the birth (such as the sex of the child and birth defects), and

those that can only be known post-natally (such as length of life, the quality of the mind, illnesses, marriage, children, and material fortunes).

Ptolemy explains the order by which each theme becomes relevant, and follows this in his arrangement of topics presented in the remaining chapters of books III and IV.

First he deals with the prenatal matters, covering the astrological significators of the parents in chapter 4, and siblings in chapter 5. Then he deals with the matters "directly concerned with the birth", explaining how to judge such issues as whether the child will be male or female (ch.6); whether the birth will produce twins or multiple children (ch.7); and whether it will involve physical defects or monstrous forms; if so, whether these are accompanied by mental deficiency, notability or honour (ch.8).

Book IV: Individual horoscopes (external accidentals)

Book IV is presented with a brief introduction to reaffirm the arrangement of content as previously described. It starts with the topics of riches and honour. Ptolemy says: "as material fortune is associated with the properties of the body, so honour belongs to those of the soul". Chapter 2, on material wealth, employs the "so-called 'Lot of Fortune'" although Ptolemy's instruction conflicts with that of many of his contemporaries in stating that for its calculation "we measure from the horoscope the distance from the sun to the moon, in both diurnal and nocturnal nativities". Ptolemy's reputation ensured this approach to calculation was adopted by many later medieval and Renaissance astrologers, although it is now realised that most Hellenistic astrologers reversed the formula of calculation for nocturnal births. It is notable that in his discussion "Of the fortune of Dignity", in chapter three, Ptolemy makes no reference to the Lot of Spirit (or Daimon), which would normally be used as the spiritual counterpart to the material wealth and happiness associated with the Lot of Fortune. This is viewed as a demonstration of his general dislike (declared in bk. III.3) for "lots and numbers of which no reasonable explanation can be given".

The subsequent chapter, the title of which is translated by Robbins as 'Of the Quality of Action', concerns professional inclinations and the significators of career advance (or decline). This is followed by the treatment of marriage in chapter 5, which is primarily referred to the Moon in a man's chart, to describe his wife, and the Sun in a woman's chart to describe her husband. Here Ptolemy shows employment of the astrological technique known as synastry, in which the planetary positions of two separate horoscopes are compared with each other for indications of relationship harmony or enmity.

The next four chapters complete the survey of natal themes, dealing with the topics of children (ch.6); friends and enemies (ch.7); the dangers of foreign travel (ch.8) and the quality (or type) of death (ch.9 – as opposed to the time of death considered in III.10).

The final chapter of the work is described as "a curious one" for introducing a separate theme at the end of the book. This refers to the seven 'ages of man', which Ptolemy briefly mentioned in III.1 as a matter which varies the emphasis of astrological configurations according to the time in life they occur: "we predict events that will come about at specific times and vary in degree, following the so called ages of life.

Criticism

Despite Ptolemy's prominence as a philosopher, the Dutch historian of science Eduard Jan Dijksterhuis criticizes the Tetrabiblos, stating that "it only remain puzzling that the very writer of the Almagest, who had taught how to develop astronomy from accurate observations and mathematical constructions, could put together such a system of superficial analogies and unfounded assertions."

Editions and translations

No original manuscripts of the text have survived; its contents are known from translations, fragments, paraphrased copies, commentaries and later Greek manuscripts. Astrological researcher Deborah Houlding, in an analysis of how specific points agree or vary between different editions, suggests that areas of conflicting details have been affected by three main streams of transmission: manuscripts that have passed through Arabic translation; those based on a paraphrased edition, and manuscripts that are dated four centuries later than the Arabic ones, but which have not undergone translation out of Greek.

Arabic translations

The oldest extant manuscript is an Arabic translation compiled in the 9th century by Hunayn ibn Ishaq. This was first translated into Latin, in Barcelona, by Plato de Tivoli in 1138 and became influential as the first complete introduction of Ptolemy's astrological work in medieval Europe. It survives in at least nine manuscripts and five Renaissance printings.

Other Latin translations made from Arabic sources include an anonymous (unpublished) work compiled in 1206 and another of the 13th century by Egidio Tebaldi (Aegidius de Thebaldis). Typically, the Latin translations made from Arabic texts were circulated with a commentary compiled by Ali ibn Ridwan (Haly) in the 11th century.

Egidio Tebaldi's translation was first published by Erhard Ratdolt in 1484 together with Haly's commentary and a "pseudo-Ptolemaic" list of aphorisms known as the Centiloquium. This has been described as "the creature of late-fifteenth-century Italian presses".

Paraphrase based editions

An anonymous Greek paraphrase is speculatively attributed to the 5th-century philosopher Proclus. It is often referred to as the Proclus' Paraphrase although its authenticity is questioned, being described as "very doubtful" by Professor Stephan Heilen. The content of the Paraphrase is close to that of manuscripts of the Tetrabiblos, but it uses simplified text with the aim of providing what Heilen calls "a more easily understandable version of the difficult original work".

There is no modern critical edition of this text. The oldest extant manuscript is dated to the 10th century and housed in the Vatican Library (Ms. Vaticanus gr.1453, S. X., ff.1–219). Some of the text of the Paraphrase was published with a Latin translation and Preface by Philipp Melanchthon in Basel, 1554, but this was not widely circulated. A full reproduction with an accompanying Latin translation was made around 1630 by the Vatican scholar Leo Allatius "for his own private gratification" and this was published by the Elzevir typsetters in Leiden, 1635, apparently without Allatius's knowledge or consent.

Allatius' Latin translation was used as the source of all English translations of the Tetrabiblos prior to the Robbins' edition of 1940. These include translations made by John Whalley (1701); the Whalley "corrected edition" made by Ebenezer Sibly and his brother (1786); J.M. Ashmand (1822); James Wilson (1828); and other 19th-century privately circulated manuscripts such as that of John Worsdale.

Greek manuscripts

Although no copies of Ptolemy's original manuscript remain, there are other ancient works, such as Hephaistio's Apotelesmatics I, which describe or reproduce some of its passages. These have been used to help verify disputed areas of content.

The oldest fairly complete Greek manuscript of the text (rather than the paraphrased edition made of it) is dated to the 13th century. Two or three others are dated to the 14th century but most are dated to the 15th and 16th centuries. In the 'Introduction' to his 1940's translation, Frank Eggleston Robbins reported the existence of at least 35 manuscripts containing all or a large part of the Tetrabiblos in European libraries.

The first printed edition was made in 1535 with an accompanying Latin translation by the German classical scholar Joachim Camerarius. This was reprinted in 1553 and is "notable for offering the first Latin translation based upon a Greek rather than Arabic source". Robbins noted the page numbers of the 1553 edition in the Greek text which faces his English translation, stating "My collations have been made against Camerarius' second edition, because thus far this has been the standard text and it was most convenient".

Also in 1940, a Greek critical edition was published by Teubner, in Germany, based on the unpublished work of Franz Boll which was completed by his student Emilie Boer. Robbins expressed regret at not being able to refer to this in the preparation of his English translation.

In 1994 the 'Boll-Boer' edition became the basis of a serialised English translation by Robert Schmidt, published by Project Hindsight. The 'Translator's Preface' was critical of Robbins' understanding of some of the "conceptual issues involved" and argued the need for a new English translation which recognised the "probable superiority of the Teubner text edited by Boll and Boer in 1940".

The most recent critical edition of the Greek text was made by the German scholar Professor Wolfgang Hübner, and published by Teubner in 1998. Based on 33 complete and 14 partial manuscripts, Hübner also incorporated the unpublished notes of Boer and the reasoning given in the Robbins and Boll-Boer editions. This is now considered the authoritative edition. A reviewer's comment in The Classical Review declares of it "Progress over previous editions is evident on virtually every page".

Associated texts

Commentary

In addition to the Arabic commentary on the Tetrabiblos made by Ali ibn Ridwan (Haly) in the 11th century,

significant attention is given to an anonymous Greek Commentary, which has older, obscure origins. It was written at an uncertain date, in either late antiquity or the Byzantine period. This is also attributed to Proclus, as the presumed author of the Paraphrase, although Heilen has remarked that such an attribution "looks like guesswork". Houlding has also pointed out that differences in tabulated information presented within the Paraphrase and the Commentary "is a telling argument that both cannot be the work of the same author".

The Greek Commentary was first printed in 1559 with an accompanying Latin translation by Hieronymus Wolf. This claimed to be based on a heavily corrupted manuscript which required numerous conjectures by a scholarly friend of Wolf, who preferred to remain anonymous rather than face reproaches for "dabbling in this sort of literature". Wolf's edition was bound with an Introduction to the Tetrabiblos, attributed (speculatively) to Porphyry, and the scholia of Demophilus.

The purpose of the Commentary was to offer demonstrated illustrations and fuller explanation of the astrological principles described by Ptolemy. Following Wolf's edition, large passages were incorporated into Latin astrological works which featured extensive collections of example horoscopes. Two notable examples are Jerome Cardan's Ptolemaei De Astrorvm Ivdiciis (Basel, 1578) and Francisco Junctinus's Speculum Astrologiae (Lugduni, 1583). Modern translators continue to make reference to the Hieronymous Wolf Commentary in their explanatory annotations.

Centiloquium

The Centiloquium 'one hundred (sayings)' was the common Latin title of a collection of 100 important astrological aphorisms. It was also known in Latin as Liber Fructus (Arabic: Kitab al-Tamara; Hebrew: Sefer ha-Peri) 'Book of the Fruit'. The latter reflected the belief that this offered a summation of Ptolemy's key astrological principles, and therefore presented "The Fruit of his Four Books". It began, as all Ptolemy's works did, with a dedication to "Syrus", which helped support the assumption of the work's Ptolemaic authenticity.

Early manuscripts were commonly accompanied by a commentary on their use authored by Ahmad ibn Yusuf al-Misri (835–912). This became translated into Latin at the same time as translations were being made of the Arabic editions of the Tetrabiblos. The earliest translations were made by Johannes Hispanensis in 1136 and Plato of Tivoli in 1138.

Ali ibn Ridwan (Haly), who had produced the Arabic commentary on Ptolemy's work, noticed that the aphorisms highlighted principles of interrogational astrology, and wondered why Ptolemy had not included coverage of these themes in his Tetrabiblos. Jerome Cardan was the first to declare the work a forgery based on such differences, referring in his commentary on the Tetrabiblos to an argument of Galen: "In the old days, kings who were trying to establish great libraries bought the books of famous men at very high prices. By doing so they caused men to ascribe their own works to the ancients".

The authorship of the text is now ascribed to "Pseudo-Ptolemy". Some scholars suggest that Ahmad ibn Yusuf was its true author. Others believe that the Centiloquium, though not Ptolemy's, may preserve some collation of authentic materials from Hellenistic astrology. Ultimately, the historical assumption that the Centiloquium was part of Ptolemy's astrological legacy gave it widespread influence in the medieval period, by which it became established as an important text within the astrological tradition.