Raglan Castle was built during the 15th century by Sir William ap Thomas and his son William. It was tranformed during the Tudor period, c. 1549-89, by William Somerset, earl of Worcester. During the English Civil War the castle was held for the King by his grandson, Henry Somerset. The Parliamentarians attacked the castle in 1646 and was eventually surrendered after a 13-week siege. Despite the damage inflicted on the castle during the Civil War, much of the hexagonal-shaped Great Tower and lavish suites of state apartments still survive.

Source:
http://www.cadw.wales.gov.uk