Castello Ursino, also known as Castello Svevo di Catania, is a castle in Catania, Sicily, southern Italy. It was built in the 13th century as a royal castle of the Kingdom of Sicily, and is mostly known for its role in the Sicilian Vespers, when it became the seat of the Sicilian Parliament. The castle is in good condition today, and it is open to the public as a museum.