"Victorious" was converted into a repair ship in 1915–1916 and based in Scapa Flow, the main base of the Grand Fleet. "Jupiter" was transferred to the Suez Canal Patrol in mid-1915, before returning to Devonport in late 1916 to be paid off. By 1916, "Illustrious" had been converted into a storeship and based in Chatham; she was joined there by "Prince George", by then converted into a barracks ship. From December 1914 to September 1918, "Caesar" was employed as a guard ship, first at Gibraltar and then in the North America and West Indies Station. She served in the Adriatic Squadron in September 1918, and then in the Aegean Squadron in October. After the war, she supported the Allied intervention in the Russian Civil War in the Black Sea as a depot ship; she was the last British pre-dreadnought to serve overseas in any capacity.