Cracovian compass of Galileo’s period. Archaeological evidence of teaching geometry and astronomy in Cracovian Academic Gymnasium

In 2007, the priceless collection of historic scientific instruments stored in Jagiellonian University Collegium Maius was enriched with a unique scholar compass, a sensational archaeological discovery made in the Cracow university quarter. The above-mentioned brass compasses, with a signature in the form of the Greek letter Ω, was found in 2005 in Cracow, in the northern courtyard of Jagiellonian University Collegium Novum. In the context of the discovery, the compasses can be related to the building, the remains of which were uncovered in the western part of the Collegium Novum courtyard. From 1589 to 1643, this building housed the oldest academic gymnasium, which is the so-called Classes, renamed as Nowodworski School after 1625. After the location of the secondary school was changed in 1643, the building was still called Old Classes until 1813, although it had not belonged to the university since 1783. The afore-mentioned secondary school, established near the Cracow Academy from 1586 to 1588, following the example of the then progressive solutions known from the University of Heidelberg, served as a so-called academic pedagogium; that is, a school preparing young people for more serious university studies. The described geometric instrument was dug up from a depth of 450 cm, within the area of a black stratum of ashes, interpreted as a usable level of the basement floor of the late Renaissance building of the academic gymnasium. It is worth mentioning that in the same usable stratum, apart from the compasses, some fragments of ceramic vessels and tiles, the technological features of which are typical for early modern ceramics, dated to the end of the 16th century, were discovered too. The determination of the origin date of the compasses is partly enabled by a numismatic item coming from the stratum that was lower, and thereby older, than the stratum of ashes. It is an old ‘rechen pfenning’, minted during the last twenty years of the 15th century. On this basis, taking into consideration not only the moment of minting, but also a certain period of using the pfennig in trade before it had been lost, it could be assumed that the stratum in which the compasses were found had been formed not later that in the mid-16th century.