The first castle was built on the site of Bewcastle Roman Fort, around 1092.

The castle is surrounded by a dry moat, the north and east sections of which re-use the Roman ditch.

It was decayed by the early 15th century when Edward IV granted it to his brother, the Duke of Gloucester, who later became King Richard III.

[1] In 1602 Thomas Musgrave was accused by Lancelot Carleton to the Privy Council of harbouring thieves in the castle.

The castle was in a state of ruin by the 17th century, and although much of the stone was removed for nearby buildings, much of the gatehouse with its internal garderobe still remains.