Trinacria is both an alternative name for Sicily and a synonym for its regional symbol, the triskelion, which also appears on the flag of Sicily.

Historically, the name Trinacria was used after the Peace of Caltabellotta War of the Sicilian Vespers.

Frederick III of Sicily was recognised as king over Sicily, with the title of "King of Trinacria." (1302) to distinguish between the two Sicilies that became a reality after that Charles of Anjou was recognised as king over the southern portion of the Italian peninsula, with the title of King of Sicily, usually rendered by historians as "King of Naples," for such was his capital.

Mythology

The Medusa in the center of the triskelion implies the protection of the Goddess Athena, the patron Goddess of the Isle. In early mythology, Medusa was the destructive aspect of Athena. Later, she was a monster slain by the hero Perseus, whose head then adorned Athena's shield.