C15 stone castle with C16 extensionsand alterations, of 4 building phases 1435-45, 1460-9, 1549-89, and c1600. Beseiged in 1646, its fall marking 'the effective end of the first Civil War'. It is possible that as first fortification was established c1070, and though the Great Tower stands on an earth motte, the date is uncertain. About 1174 Raglan was held by Walter Bloet, of the Norman family possessed of extensive lands in England, and the Bloets held it until the late C14 when Elizabeth Bloet (d 1420) married successively Sir James Berkeley (d 1405) and Sir William ap Thomas (d c1445). Before the C15 there was a manor house on the site, but with the possible exception of the lowest courses on the S gate nothing survives. Sir William ap Thomas fought at Agincourt in 1415, was knighted in 1426, and in 1432 bought the manor from the Berkeley family and built the hexagonal Great Tower, or 'Yellow Tower of Gwent' and the S gate. His son William Herbert amassed a fortune from trade and financed Edward IV in his bid for the throne. After Edward's accession in 1461, already lord of Usk and sheriff of Glamorgan, he became Chief Justice and Chamberlain of South Wales, and was granted Pembroke, the Gower and other lordships. His role in the elimination of Lancastrian power in Wales gained him in 1468 the Earldom of Pembroke, and he also bought the castle and lordship of Chepstow, making the Herbert family by far the most powerful family in Wales. He lavished money on the building programme, continuing his father's work such that the buildings of c1432-69 form the most substantial part of the castle, united by their polygonal towers. The Earl altered the Great Tower, completed the Fountain Court and built the major part of the Pitched Stone Court. William was executed after the Yorkist defeat at Edgecote in 1469, but his son William (d 1491) prospered with the Yorkist return. He exchanged the earldom of Pembroke for that of Huntingdon. His brother Sir Walter Herbert (d 1507) held Raglan from 1491, entertaining Henry VII's Queen there in 1502. His niece Elizabeth inherited. Her husband, Charles Somerset (d 1526), was Lord Chamberlain to Henry VII and Henry VIII, ennobled in 1504 as Lord Herbert and in 1514 became Earl of Worcester. The 2nd Earl, d 1548, acquired the lands and abbey of Tintern and the 3rd Earl (d 1589) was responsible for the final major works to the castle: the remodelling of the hall, with new buttery and the long gallery above, the office wing in the Pitched Stone Court, together with an ambitious programme of formal gardens. The 4th Earl, d 1628, a Catholic, but Master of the Horse to Elizabeth and James I, Lord Great Chamberlain to Charles I, and patron of Edmund Spenser and William Byrd. He completed the interiors and made minor changes to the basic structure. The 5th Earl raised vast sums for the Royalist cause in the Civil War, becoming 1st Marquis of Worcester and Duke of Somerset. His son Lord Herbert became Earl of Glamorgan: Herbert was the noted inventor whose 'Centurie of Inventions' (1663) includes a prefigurationr of the steam engine. After a famous siege Raglan fell to General Fairfax in August 1646 and the whole castle deliberately ruined thereafter.
After the Restoration the Somerset family, Dukes of Beaufort from 1682, made their main residence Badminton House in Gloucestershire, leaving Raglan to be plundered for building stone until this was stopped by the fifth Duke after 1756. His youngest son was the noted soldier, created Lord Raglan in 1852, commander of the British forces in the Crimean War. Cefn Tilla was purchased for Lord Raglan as a reward for his services.