The naval Battle of Ostia takes place in 849 between some Saracen pirates and an Italian league of Papal, Neapolitan, Amalfitan and Gaetan ships.

The battle ends in favor of the Italian league, as they beat off the pirates.

It is one of the few events to occur in southern Italy during the ninth century that is still remembered today, largely for the walls named after Leo and for the Renaissance painting Battaglia di Ostia by Raphael.