Since the ninth century, the Duchy of Croatia (later Kingdom) engaged in naval battles, struggling to maintain control over the eastern Adriatic coast and Adriatic merchant routes. Commemorating the first recorded Croat naval victory, when the subjects of Croatian duke Branimir defeated the Venetian naval expedition on September 18, 887, the Croatian Navy Day is celebrated yearly on September 18. Croatian fleet was particularly active under duke Domagoj and king Petar Krešimir IV. Royal Croatian-Dalmatian navy with 12-15 galleys existed under Louis I in central Dalmatia in the 14th century. Afterwards Venetian Republic established control over most of Croatian coast until 1797. Modern foundations of Croatian Navy can be traced back to Austro-Hungarian Navy (1797–1918) and Yugoslav Navy (1918–1941, 1942–1991) when Croatia was a constituent part of these states.