Kleanthi-Schaubert, or the ‘Old University’, is located on Tholou street in one of the highest sections of Plaka. Built in the 17th century, the institution was purchased by two close friends, who happened to be architects. After arriving in the newly liberated Athens, Kleanthis and Schaubert went to work on the old building, repairing and restoring its huge walls and the vaulted basements, adding other buildings and uniting them all into a single complex.

The building housed the Girls High School and, later, the university. In 1837, three new rooms and a medical theatre were added.

When the university finally moved to its own building after 1841, the original Kleanthis House took on other uses, including serving as an army barracks. The facilities changed hands many times over the years, until it was declared a listed building 1963. In 1967 it was officially assigned to the university, and has since between restored, now housing the university’s History Museum.