Sea, the Irish Sea and in the Mediterranean. The German U-boat threat was drastically reduced when the British finally adopted a convoy system in early 1917. There was one great battle in the waters near Europe: the Battle of Jutland 31 May 1916 – 1 June 1916 between the German High Seas Fleet and the British Grand Fleet. This was one of the largest sea battles in world history though, in some respects, the battle was inconclusive. In the Adriatic, some very limited sea combat took place between the navy of Austria-Hungary and the Allied navies of France, Britain, and Italy. The strategy of the Allies was to blockade the Adriatic and monitor the movements of the Austrian fleet. In general, this strategy was successful but the Germans and the Austrians were able to send submarines out into the Mediterranean where they did some damage. The main sea base for the Austrian and German fleet in the Adriatic was Pola (modern day Pula in Croatia). Japan, an ally of the United Kingdom, sent some destroyers to the Mediterranean and they were very effective in patrol and anti-submarine activity. By contrast the Italian Navy was "languid and apathetic" (Cyril Falls "The Great War" p. 295). The only significant naval battle occurred on 15 May 1917 when three Austrian cruisers under Captain Miklós Horthy staged a raid on some Italian and British transports near Valona Albania. The raid was a partial success but the raiders were nearly destroyed by shell fire from Italian ships that chased them back to Pola. In the Black Sea, the Russian fleet was dominant and it was led by two skilled commanders, Admiral Eberhart and then Admiral Kolchak (who took over in 1916). By the end of 1915, the Russian fleet had nearly complete control of the sea. The Black Sea fleet was used mainly to support General Yudenich in his Caucasus Campaign. In the Baltic Sea, the Russian fleet was essentially inactive, hiding behind the belts of mines which stretched across the entry into the Gulf of Finland. So the German Baltic fleet dominated the sea and was of occasional use to the German army on the Eastern front. See also Finnish Civil War World War I Europe References Campaigns and theatres of World War I 1910s in Europe