The armillary sphere was part of the collection of scientific instruments with which Lancisi equipped the library. Created in the 16th century by Simone Barocci from Urbino, it was used to demonstrate and study the movements of the celestial sphere in relation to the Earth, which was placed at the center. Composed of a framework of graduated metal rings (armillae), the artifact reflected the state of astronomical knowledge in the mid-16th century, still based on the geocentric model of the universe.
