Aci Castle, locally known as Castello di Aci, lies on a cliff in the coastal town of Aci Castello, in the Catania province on the island of Sicily in Italy.
The first fortification at this site might have been a Byzantine fortress. It is known that there was one in Aci which resisted the Muslim conquest of the island but which was destroyed in 902 A.D. by the Emir Ibrahim.
Aci Castle was built by the Normans after they conquered the area from the Muslims. The Norman castle was first mentioned in 1092, when it was granted to Ansgerio da S. Eufemia, Bishop of Catania, by the Norman count Roger I of Sicily. In 1169 a lava eruption struck the area. The lava reached and partially engulfed the castle cliff which until then had stood isolated from the mainland.
In the early 13th century, Aci Castle would have undergone significant renovations after town and castle had become part of the royal domain of Frederick II, Holy Roman Emperor and King of Sicily.
During the few decades of Angevin rule over Sicily, the castle had been back in the possession of the bishops of Catania. But after the Sicilian Vespers revolt in 1282 the Aragonese king, Peter III of Aragon, granted the castle to Admiral Roger of Lauria, as a reward for military enterprises. When, in 1296 Roger sided with the Angevins, the castle was sieged by Frederick III of Sicily. He took the castle with the use of siege towers.
In 1320 Aci Castle and the town were granted by Frederick III to Blasco Alagona. In 1354 the castle was attacked and severely damaged by Marshal Aciaiolu, who had been sent to Sicily by Louis I, Duke of Anjou. In 1396, during the absence of Artale Alagona II, the troops of Martin I of Sicily conquered the castle by poisoning its water supply, after which they set fire to the castle.
After the death of his wife Maria of Sicily, Martin I resided frequently in Aci Castle with his 2nd wife, Blanche I of Navarre. In 1416 the castle was restored. In the last quarter of the 15th century the castle was equipped with a garrison and used as a prison.
In 1634 Aci Castle underwent a large scale renovation. In 1647 the castle was sold to Giovanni Andrea Massa. A large earthquake shook eastern Sicily in 1693 and also damaged the castle, which was subsequently repaired by the descendants of Massa.
In the 19th century Aci Castle was acquired by the town. In 1818 another earthquake again caused considerable damage to the castle, which made it unfit to be used as a prison anymore.
In the 20th century the castle was restored and turned into a small museum.
At present Aci Castle can be visited for a small fee. A nice castle on a great location.