arisbrooke Castle was originally a Roman fort. The castle is located in the centre of the Isle of Wight and was put up soon after William the Conqueror came to England. The Earl of Hereford, William Fitz Osbern may have been responsible for its construction, but he was killed in battle during 1070/1071 and so would have had little opportunity to oversee the construction. Osbern's son, Roger, is more likely to have built or refortified the castle. It was at Carisbrooke Castle that William arrested his own half brother, Odo for acts of treason. Henry I granted the castle in the first year of his reign to Richard de Redvers. The Redvers family owned the castle for much of the Medieval period, only ending in November 1293 when the last Redvers, Isabel died. In 1136, Baldwin de Redvers took refuge in the castle on the run from King Stephen. Unfortunately the wells on the island ran dry and Baldwin gave up the land in exchange for his head. Baldwin's land was restored to him in 1153 when Henry II became king. Baldwin, the last male in the line, died in 1216 poisoned, it is said by Peter of Savoy. Isabella de Fortibus, Baldwin's sister took control of the castle and successfully ran it until her death in 1293.

In the reign of Queen Eliabeth I, the Italian engineer Federigo Gianibelli was employed to improve the earthwork defences around the castle. The modifications were designed to make it harder for cannons to fire in a direct line at the walls of the castle. The outer gateway was also rebuilt in the Elizabethan period.

Carisbrooke Castle served as the prison for Charles I after he was captured trying to flee the country. In more recent times the castle was the home of the governors of the Isle of Wight, the last of whom was Princess Beatrice, daughter of Queen Victoria.

Yarmouth Castle is located on the eastern side of the River Yar estuary on the Isle of Wight and was built by King Henry VIII in around 1547 to protect the island from invasion by the French. The French had landed on the Isle of Wight briefly a couple of years earlier and it was probably this event that Henry has reacting to. It is one of a series of gun-forts that Henry had built to protect the whole of the south coast. Hurst Castle, another of Henry's gun-forts is located on the other side of the Solent. Like other gun-forts built at the time, Yarmouth Castle was designed not as a residence but as a platform to hold large guns, but its shape is completely different. While most of the other gun-forts had a circular central tower, Yarmouth Castle has a square tower with 100 feet long sides.