The Sicilian flag has a long history dating back at least until the Sicilian Vespers in 1282. The two main colours, red and yellow, represented, respectively, Palermo and Corleone, the two founding cities of the confederation against the Angevin rulers (Corleone was one of the island's most important agricultural centres at the time).
The three legs of the central figure represent a "trinacria", or triangle, from the Greek name for Sicily, "Trinakrias". The face in the centre was originally that of Medusa, but now has a softer look.
During the Sicilian Vespers the flag became the true symbol of the island's unity against the Angevin French. At Messina the colours took on even greater significance as Sicilians flooded there to defend against the advance of the Papal army, sent to reinstate the disgraced Angevins. The flag was draped over the city's walls and the Sicilians managed to hold out against the siege for five months. Consequently, the colours remained fundamental for the city itself.
In 2000 the Regional Government of Sicily officially adopted the flag and since then it has hung from all official buildings.