Originally wooden vessels protected by iron plates; they were used at the siege of Gibraltar in 1782; the French had them in the Crimean War, and in 1858 built four iron-plated line-of-battle ships; in 1860 England built the Warrior , an iron steam battleship with 4½-inch plates; since then new types have succeeded each other very quickly; the modern ironclad is built of steel and armed with steel plates sometimes 2 feet thick; the term is now loosely applied to all armoured vessels, whether battleships, or cruisers, or gunboats, and whether of iron or steel.