The first ironclad battleship, with iron armour over a wooden hull, "La Gloire", was launched by the French Navy in 1859 prompting the British Royal Navy to build a counter. The following year they launched HMS "Warrior", which was twice the size and had 4.5 inches of wrought iron armour (with 18 inches of teak wood backing) over an iron hull. After the first battle between two ironclads took place in 1862 during the American Civil War, it became clear that the ironclad had replaced the unarmoured line-of-battle ship as the most powerful warship afloat.