By the time Henry II Plantagenet (r. 1154–89) was crowned king of England in 1154, baronial castles outnumbered royal castles. A tough, dynamic ruler, Henry began to rectify the situation at once. In the north, King Malcolm of Scotland surrendered to him, giving Henry significant castles in Scotland and in the border territory. Many older castles like Windsor were strengthened. At Dover the masonry great tower and fore building were built in the 1180s, and concentric walls with half-round towers were added by Richard the Lion Hearted seventeen years later.

Ch. 1 : The Great Tower : Norman and Early Plantagenet Castles - Medieval castles (2005)