Old city landmarks include the city hall on Markt Square and the Hohentübingen Castle, now part of the University of Tübingen. The central landmark is the "Stiftskirche" (Collegiate Church). Along with the rest of the city, the Stiftskirche was one of the first to convert to Martin Luther's protestant church. As such, it maintains (and carefully defends) several "Roman Catholic" features, such as patron saints. Below the "Rathaus" is a quiet, residential street called the "Judengasse", the former Jewish neighborhood of Tübingen until the city's Jews were expelled in 1477. On the street corner is a plaque commemorating the fate of Tübingen's Jews.