After the end of the civil wars, Augustus reduced and reorganized the Roman armed forces, including the navy. A large part of the fleet of Mark Antony was burned, and the rest was withdrawn to a new base at Forum Iulii (modern Fréjus), which remained operative until the reign of Claudius. However, the bulk of the fleet was soon subdivided into two praetorian fleets at Misenum and Ravenna, supplemented by a growing number of minor ones in the provinces, which were often created on an "ad hoc" basis for specific campaigns. This organizational structure was maintained almost unchanged until the 4th century.