A square inscribed in a circle, the resulting figure divided into four quadrants by two perpendicular axes, with eight triangular sectors in the spaces between the circumference and the sides of the square. This is the fascinating geometrical representation, charged with symbolism, of a garden-cosmos that has become a model of balance and measured beauty. A green world reflecting the humanistic culture of the time, the univerxsity botanical garden of Padua is the oldest in the world, the only one to have remained in its original location, and since 1997 has been a Unesco World Heritage Site.

On 29 June 1545, the Senate of the Venetian Republic established the horto medicinale or hortus simplicium in Padua, on land belonging to the Benedictine monks of Santa Giustina, near the basilica of St Anthony. The heart and the revolutionary essence of the venture lie in therapeutic plants, which had been studied since 1533: in effect, the University of Padua set up a Chair of Lectura Simplicium so that students could be given lessons in medical botany, applying an experimental approach that involved the direct observation of plants described in ancient writings.

The planning of the garden is attributed to the Venetian patrician Daniele Barbaro, but other illustrious scholars contributed to the project: professor Francesco Bonafede, holder of the Lectura Simplicium chair, botanist Luigi Squalermo, known as Anguillara, the first Prefect in 1546, Pier Antonio Michiel, for the decoration and layout of the plants, and Bergamo architect Andrea Moroni, who was involved in the actual works and engaged at the time on the construction sites of the basilica of Santa Giustina and the Palazzo del Bo.