The ridge at Carisbrooke was fortified long before the surviving stone castle. Archaeology indicates occupation in Roman times, while an Anglo-Saxon defensive enclosure, or burh, was established around the year 1000 as protection against Viking raids. After the Norman Conquest, the site became the center of a powerful island lordship. A Norman earth-and-timber castle occupied the earlier enclosure, controlling routes across the Isle of Wight and providing a base from which its lords could govern an island exposed to seaborne attack.

Around 1100, Baldwin de Redvers and his successors developed Carisbrooke in stone. The keep rose on its motte, and walls, gates, domestic buildings, and a chapel gradually transformed the stronghold. When Baldwin rebelled against King Stephen in 1136, the castle surrendered after its well ran dry, a lesson later addressed by improving the water supply. During the thirteenth century, the de Redvers heiress Isabella de Fortibus made Carisbrooke an important residence and administrative center. After her death in 1293, the estate passed to Edward I and remained a royal possession.

The castle’s defenses mattered because the Isle of Wight was repeatedly threatened during the wars with France. French forces raided the island several times in the fourteenth century and besieged Carisbrooke in 1377, but the stronghold held. Later medieval governors repaired its walls and organized local defense. In the 1580s and 1590s, renewed danger from Spain prompted Governor George Carey to modernize the site. An angular artillery enclosure was built around the medieval core, adapting Carisbrooke to cannon warfare and making it one of England’s most substantial Elizabethan defensive works.

Carisbrooke’s most famous prisoner arrived in November 1647. King Charles I, having fled Parliamentary custody, initially came to the Isle of Wight expecting negotiation or support. Instead, he was confined in the castle. Charles attempted to escape twice, on one occasion becoming stuck between the bars of a window, while secret discussions continued over the political settlement of the kingdoms. He was moved to Newport in 1648, then taken back to the mainland and executed in January 1649. Two of his children, Elizabeth and Henry, were subsequently held at Carisbrooke; Elizabeth died there in 1650.

Military importance declined after the seventeenth century, although governors and caretakers continued to occupy parts of the complex. The government placed the castle under official care in the nineteenth century. Princess Beatrice, Queen Victoria’s youngest daughter, became governor of the Isle of Wight in 1896, opened a museum in 1898, restored the chapel as a memorial to Charles I, and later used the castle as a summer residence. Conservation and archaeological work have since preserved its layered remains. Carisbrooke now presents an unusually continuous record of island defense, aristocratic lordship, royal imprisonment, and public commemoration.