In early 1915, "Majestic" and "Prince George" took part in the Dardanelles Campaign against the Ottoman Empire; they bombarded Ottoman positions around the Dardanelles until May, when "Majestic" was torpedoed and sunk by the German U-boat off Cape Helles. At around the same time, "Prince George" was hit by a shell from an Ottoman coastal battery, requiring repairs at Malta. "Hannibal", "Magnificent", "Victorious", and "Mars" were laid up in early 1915 and had their 12 in guns removed to arm the "Lord Clive"-class monitors. "Illustrious" was similarly disarmed, with two of her guns going to the Tyne Turrets. "Hannibal", "Magnificent", and "Mars" were then used as troop ships during the operations off the Dardanelles. In late 1915 after the conclusion of the Dardanelles Campaign, "Hannibal" was stationed in Egypt as a depot ship, while "Magnificent" and "Mars" returned to Britain to be used as an ammunition ship and a depot ship, respectively.