The Normans imposed a new weapon on the Welsh landscape, the castle, soon copied by the Welsh Princes as they fought the invaders, and each other. In its earliest form this was a mound of earth (the motte) topped with a timber tower and often supported by an enclosure surrounded by a bank and ditch (the bailey). The stone castle developed from this and became increasingly complex over succeeding centuries. Boroughs, where markets could be controlled and taxed were established outside castles and soon grew into towns. This period also sees the rise of the church as a building and institution, reaching the height of its importance in beautiful cathedrals and monasteries.