 The Great Tower at Raglan Castle , sometimes called the Yellow Tower of Gwent , sits outside the rest of the castle , protected by a moat and linked to the Fountain Court by a bridge . The fortification is representative of a trend during the 15th and 16th centuries in British castle building : tower keeps such as this , large , solid buildings designed for private accommodation , probably inspired by those in France , had started to appear in the 14th century at Dudley and Warkworth . In the 15th century the fashion spread , with the creation of French @-@ influenced palatial castles featuring complex tower keeps , such as those at Wardour and Tattershall . These were expensive buildings to construct , each built to a unique design and , as historian Norman Pounds has suggested , " were designed to allow very rich men to live in luxury and splendour " . 
