Dover is a giant among castles. It has the longest recorded history of any major castle in Britain. Indeed Dover Castle began before history itself, its earliest rampart defences date back to the prehistoric Iron Age. Then the Romans built a pharos (lighthouse) here in the first century AD. The same tall headland, already partially defended, was resettled in the tenth century or earlier by the Anglo-Saxons. They built a burh, a fortified town, of which St Mary-in-Castro was the church.The bulk of Dover Castle, as we know it today, dates from a century after the Norman Conquest. Soon after the Battle of Hastings, in the autumn of 1066, William the Conqueror spent eight days at Dover strengthening fortifications which had only recently been rebuilt by the defeated Harold. Yet neither William's works nor those of Harold are identifiable today and, with the exception of the church and pharos, the masonry of Dover Castle dates from the twelfth century or later.Most monumental is the great square tower, or keep, built in the 1180s for King Henry II (1154-89). Also of the1180s are the walls of the keep's surrounding court (the inner bailey), as is a stretch of outer curtain wall towards the east. The remainder of this substantial outer curtain, with its sophisticated gate houses and many flanking towers, is chiefly the work of Hubert de Burgh, Constable of Dover (1202-32), and his successors under Henry III. After the thirteenth century little of substance was added to the Castle before the present barracks were built and the defences remodelled, starting in the 1740s. It was then that the Castle, after years of neglect, entered a new lease of life. The Georgians and Victorians stripped Dover bare, towers were lowered to create positions for artillery and the outer defences strengthened.The Castle continued in use as a military base until the second half of the twentieth century. The underground tunnels cut into the cliffs in Napoleonic times came into their own during the Second World War as a bomb proof base for military command in the area. After the war the barracks within the Castle fell into disuse and some were demolished. However it wasn't until the end of the Cold War that the castle's defensive role finally came to an end when the Regional Centre of Government, deep in the cliffs, which would have been activated in the event of a nuclear war, was decommissioned.The Castle is now a major tourist attraction.