In the first phase of Henry’s fortification programme 30 castles or forts were built. A curvilinear form of fortification was developed which consisted of squat artillery towers surrounded by round bastions to provide platforms for artillery. Good examples of these are Walmer Castle and Deal Castle in Kent, Calshot Castle and Hurst Castle in Hampshire and St Mawes Castle in Cornwall. The Castles of the Downs consisted of Deal Castle, Sandown Castle, Kent and Walmer Castle, which created a defensive line to protect the good landing grounds and strategic anchorage between the Goodwin Sands and the coast (known as the Downs). They were linked by earthworks and bulwarks to provide further defence along this important stretch of coastline.