Palazzo Castellani, home to the Institute and Museum of the History of Science since 1930, now the Galileo Museum, is a building of ancient origins (late 11th century). Known in Dante's time as Castello d'Altafronte, after the family that owned it until 1180, when it passed into the hands of the Uberti family, the castle was part of the city's oldest city walls. After passing from the Uberti family to the Castellani family in the 14th century, it was the seat of the Giudici di Ruota from 1574 to 1841, as the ancient insignia of the two magistrates walled in the palace's entrance still recall. There is no information on the building's functions in the 17th and 18th centuries. The palace underwent significant restoration during the first half of the 19th century. After the unification of Italy, the manuscript collections of the National Library were transferred there, where they remained until the 1920s. Palazzo Castellani also housed the Accademia della Crusca and the Deputation of National History for Tuscany. The Galileo Museum now occupies the entire building, which has been progressively restored and upgraded to make it functional for its activities. Restoration work on the basement, completed in 2002-2003, brought to light the four massive stone foundation arches of the ancient Castello d'Altafronte. Located in the heart of Florence, on the Arno River, next to the Uffizi Gallery, the palace is a medieval structure with an exposed stone façade. The complex is divided into six levels, each featuring arched windows with ashlar arches.