Fig. 1: A leaf from Volume XII of Aldrovandi's Hortus Siccus, preserved in the Herbarium of Bologna University. (Credit: Sistema Museale D'Ateneo - Università di Bologna)

For the academic year 1553-1554 Aldrovandi was offered the chair of Logic but he refused it, preferring to read about logic at home for the entire year.
His teaching at Bologna University did not begin until 1554-1555. The following year he obtained the chair of Philosophy and in 1556 he also began to give free lessons on the extra-curricula course of "Reading of Simples", i.e. the study of medicinal plants from which "simple" elements are extracted and then mixed together in the preparation of "composite" medicines.

In 1561 students on this course requested that it become a recognised course of ordinary study, given its extreme usefulness to their studies. On 22 February of that year, half-way through the academic year, Ulisse Aldrovandi inaugurated the first ordinary chair of Natural Science at Bologna University, with the name of Lectura philosophiae naturalis ordinaria de fossilibus, plantis et animalibus.

Alongside his teaching activities at the University, Aldrovandi's investigative spirit led him to undertake intensive empirical activities. He played an active role in the debate on the study of natural things, which focused particularly on the Averroes interpretation of the writings of Aristotle. This interpretation expressed the need for the study of nature "juxta propria principia", i.e. with no metaphysical or religious conditioning. Aldrovandi fully supported this new way of relating ourselves to "natural things" and dedicated much of his time to organizing journeys and excursions which, on the one hand allowed him to collect material for his herbarium and his museum, and on the other hand took him on visits to experts and scholars of natural science with whom he could exchange knowledge.

From 1567 onwards, Aldrovandi followed his theoretical lessons with a practical session in which he showed in practice what he had explained to his students during the lesson. Therefore, the need for a Public Botanical Garden, where the plants used in these sessions could be grown and picked, became more and more important. Aldrovandi succeeded where his predecessor as professor of the extraordinary Reading of Simples course, Luca Ghini, doctor and eminent 16th century botanist, had failed: at Aldrovandi's suggestion, in 1568 the Bolognese Senate opened the Botanical Garden, run for the first 38 years by Aldrovandi himself. The first location of the Garden was in the town centre in a courtyard of the Palazzo Pubblico, roughly where the Sala Borsa is situated today. It was near the lecture hall where Aldrovandi taught.

Fig. 2: Town Hall of Bologna, copper engraving 1757. (Credit: Bologna racconta)