The flag of Ceuta is the flag of the Spanish city of Ceuta, consisting of a black and white gyronny with a central escutcheon displaying the municipal coat of arms. The civil flag omits the escutcheon. The gyronny is identical to that of the flag of Lisbon, to commemorate the conquest of the city by the Portuguese in 1415. The city was a part of the Portuguese Empire until 1640, after which it decided to remain with Spain. Thus the coat of arms of the city is almost the same as that of the Kingdom of Portugal, showing the seven castles and the five escutcheons with silver roundels.
Source: Wikipedia