In March 1912, "Caesar" was reduced to reserve in the 4th Squadron, Home Fleet. Later that year, "Majestic", "Prince George", and "Illustrious" were assigned to the 7th Battle Squadron (BS). Following Britain's entry into World War I in August 1914, "Caesar" and "Jupiter" were assigned to the 7th BS, which was in turn assigned to the Channel Fleet and tasked with protecting the British Expeditionary Force as it crossed the English Channel to France. At the same time, "Hannibal", "Mars", "Magnificent", and "Victorious" were assigned to the 9th Battle Squadron and stationed in the Humber to protect the British coast. "Illustrious" was instead used as a guard ship for the Grand Fleet, and was initially based at Loch Ewe.