The Reşadiye class was a group of two dreadnought battleships ordered by the Ottoman Empire from Britain in the 1910s. The design for the ships was based on the British King George V-class battleships, although it incorporated several significant improvements. They carried the same 13.5-inch (340 mm) main battery guns as the British ships, but their secondary battery consisted of 6-inch (150 mm) guns, compared to the British vessels' 4-inch (100 mm) pieces. The first ship, Reşadiye, was laid down in 1911 and completed in August 1914, shortly after the outbreak of World War I; she was seized by the British Royal Navy and commissioned as HMS Erin. The second ship, Fatih Sultan Mehmed, had only been ordered in April 1914 and little work had been done by the start of the war, so she was quickl