King Charles's Castle

The ruins of a mid-16th century coastal artillery fort, later garrisoned - hence the name - by Civil War Royalists.

Although taking its name from its occupation by Royalist forces in 1651, this small artillery fort was probably built 100 years earlier, during the reign of King Edward VI (1547–53).

It was intended to protect the narrow strait leading past New Grimsby harbour and on towards St Mary’s, but proved to be badly sited to withstand attack or to fire on ships in the channel below. 

Its guns would have to point down at so steep an angle to hit ships in New Grimsby Channel that the cannonballs would have rolled out of the cannons before they fired.