Pisan cross

It was the coat of arms of the people of Pisa, granted to them by Pope Benedict VIII to fight Saracens in Sardinia in 1017.

Its symbolism is unknown; the cross itself may represent Christ, and the twelve spheres his Apostles.

Although the Pisan cross itself dates to 1017, the oldest surviving representation is a carving on the city walls, built in 1156 by counsellor Cocco Griffi.

The city flag, red with the white cross on it, was officially recognized by Pope Callixtus II.

It also appears in the lower-right quarter of the ensign and coat-of-arms of the Italian Navy, which combines it with the emblems of the other medieval Maritime Republics: Venice, Genoa and Amalfi.