During the first half of the 1200's under Frederick II, Ursino Castle was a masterly amalgamation of Eastern and Western design symbolically and geometrically. Frederick II was known for his multicultural, multiethnic style of governing.
This mighty structure was originally on a promontory overlooking the sea for maximum security and defense: in fact, the castle's original Latin name was "Castrum Sinus", which translates as "Gulf Castle". Constructed of a mighty inner square with four large outer round towers, four slightly smaller turrets and surrounded by a moat, was a state of the art fortress in its days.
Its distance from the sea now is due to an earthquake in 1600, and Etna eruptions. Lava flowing right up to the castle, buried a part of it, filling the moat, covering and enlarging the coastline, creating a greater distance between the sea and the castle. The castle was also the scene of political change when Frederick III was proclaimed king.
Later, it became the home of the Spanish Aragon dynasty. The Isle of Sicily's inexorable decline, after the sixteenth century (from which it recovered in the eighteen hundreds), affected the Castle, which lost its role as a point of defense. Perhaps it was better suited to the warfare of catapults, crossbows and boiling oil, than to the longer range gunpowder of later years.
It became a prison for a short while in the eighteen hundreds, before being transformed into it's present capacity as a museum, and venue for art exhibitions.