Major Anglo-Norman castle, mostly late C12 to early C13. Pembroke was taken by Roger de Montgomery in 1094, and the first castle is said to have have been first built by his son Arnulph in the reign of Henry I, i.e. after 1100, but the site was besieged in 1094 and 1096 which suggests that the castle was begun at once. Arnulph was removed in 1102, and in 1105 Gerald de Windsor was appointed Royal Steward. The Earldom and County Palatine of Pembroke was created in 1138 with Gilbert de Clare as first Earl, succeeded in 1148 by his son Richard Strongbow, conqueror of Ireland. Henry II stopped at Pembroke on his way to and from Ireland, 1171-2. Strongbow's heiress married William Marshal, and he and his sons held the earldom 1189-1245, during which time the greater part of the castle was built. William Marshal is said not to have visited the county until 1204, but to have built a large part of the castle before his death in 1219. It is not certain how much had been built already in stone by the de Clares, possibly the Norman Hall, probably nothing of the structure that survives now. William Marshal was followed successively by his sons William II (died 1231), Richard (murdered 1234), Gilbert (died 1241) and Walter (died 1245) before passing to his daughter Joan, married to Warine de Munchensy. Much of the inner castle was built during this period: the Great Keep and walls of the inner ward in William Marshal's time, the rest of the Inner Ward under his sons, the Northern Hall perhaps in Joan's time. Joan, daughter of Joan and Warine, married William de Valence, half-brother of Henry III, who took over his wife's estates in 1265, and was earl to his death in 1296. From his time probably dates the walling of the outer ward, and the Great Gatehouse. Joan died in 1307, her son Aylmer de Valence died in 1324 and the earldom then passed to his nephew Laurence Hastings. During the C14 the earls were largely absent and the castle declined, though repaired when attack was feared from France in 1377 and 1405. Passed in 1335 to John Hastings, died 1375, and to John's son John , an infant. When John II died in 1389 aged 18 the earldom reverted to the crown: held by John son of Henry IV and from 1414 by Humphrey Duke of Gloucester, died in prison 1447. In 1453 Jasper Tudor, half-brother of Henry VI was made earl. Jasper's nephew, the future Henry VII, was born at Pembroke in 1456 and brought up there to 1471. During the Yorkist period William Herbert was made earl in 1461, beheaded 1469. Jasper Tudor recovered his earldom in 1485 and it reverted to Henry VII on Jasper's death.
The castle was unroofed by 1600 but repaired and played a prominent role in the Civil Wars 1642-9. Held for Parliament in the first Civil War 1642-6, the Parliamentary commanders, Laugharne and Poyer, declared for the king in 1648. The castle was besieged by Oliver Cromwell and surrendered 11/7/1648. Then partly dismantled, it remained ruinous until a partial restoration for J R Cobb in 1880-83. The full restoration began in 1928 when Major-General Sir Ivor Philipps of Cosheston Hall bought the ruins.