5 - Astronomy and Astrology in Italy and in Bologna in the XIIIth and XIVth centuries.

In the XIIIth century astrology was undoubtedly a highly respected "art" in Italy. We need only think of the ties between Frederick II and Michael Scot, those between Guido da Montefeltro and Guido Bonatti or even the fact that already in 1303 the municipality of Bologna had its own astrologer, Johannes de Luni (XIII-XIV cen.), son of Guilielmus de Luni (23).

It should furthermore be noted that in this period astrology had many more ties with public government - the Princes wanted to know their "fortunes" - than with private interests, medicine especially. This is attested by the list of possible uses for a horoscope, as laid out in the treatises of Guido Bonatti and Bartholomeus de Parma.

A different attitude comes to the fore at the beginning of the next century. Both Pietro d’Abano (1250-1315), the famous Paduan professor of Medicine, and Francesco Stabili, better known as Cecco d’Ascoli, displayed enormous interest for what would be called "medical astrology". Cecco d’Ascoli did in fact write: "It is indispensable that the physician knows and examines the course of the stars and their conjunctions so that he has an idea of the various diseases and the critical days"; adding also the saying attributed to Hipparcus: "a physician without astrology is like an eye that cannot see". (24)

Medical astrology involved the use of horoscopes and this called for a more detailed understanding of mathematical astronomy than had been the case when the discipline had been broached for its cultural content, within the context of the liberal arts.

It was in particular necessary to teach the procedures for calculating the longitudes of the planets and the use of the astrolabe - that wonderful analogic calculator that could determine, at any given hour of any day of the year, the positions in the sky of the stars, planets and ecliptic, and whose working principles, based on the most advanced applications of Greek geometry, remained a mystery to most people.

All of this is confirmed by a comment on the Theorica Planetarum of Gerard of Sabbionetta (XIII cen.) written in 1318 by Thadeus de Parma for the students of Medicine in Bologna (25). This short treatise explains how it is possible to obtain, by easy graphical procedures, the longitudes of the planets using the Ptolemaic system.

From an institutional point of view things were also beginning to rapidly take shape. In 1287 the Università degli Artisti was granted the same privileges the Università dei Legisti had enjoyed since 1150 (26). In 1289, for the first time, the municipality provided a salary for the teaching of Medicine. In 1334 this privilege was extended to lecturing in Astrology which thus became the ninth salaried discipline at the university; the courses probably took place in today’s via IV Novembre, then via Porta Nova, where lessons of the schools of Medicine, Philosophy and Rhetoric were also held, as witness the memorial tablets that can be found there today (27). In 1379 Blasius de Parma, better known as Biagio Pelacani (?-1416), was appointed lecturer in both Philosophy and Astrology, confirming the close ties between lecturing in astrology and medical studies.

  1. - M. Sarti e M. Fattorini: op. cit., I, p. 585.
  2. - L. Thorndike: 1949, The sphere of Sacrobosco and its commentators, Chicago, p. 344.
    "E' inevitabile che il medico conosca ed esamini il corso delle stelle e le loro congiunzioni affinché abbia nozione delle diverse malattie e dei giorni critici"; "il medico senza l'astrologia è simile ad un occhio incapace di vedere".
  3. - L. Thorndike: A history of magic and experimental science op. cit., III, 12.
  4. - A. Pazzini: 1956, Studi e Memorie per la Storia dell'Università di Bologna, I, p. 391.
  5. - A. Gaudenzi: op. cit., p.31.