During the 12th and 13th centuries many knights went to the Holy Land as part of the Crusades. There they saw new ideas for castles. In particular, new castles were built without a keep or motte. Instead, two rings of walls were built, the inner one higher than the outer. Towers were built along the walls to act as homes for the high officials during peace and independent 'keeps' during attack.
The ideas were put into practice in Britain when England went to war with Wales. Edward 1st built a string of castles known as the 'ring of stone'.
