However, the remains of a large 5th and 6th century settlement and the quantity of imported luxury goods found, suggest that this may have been a stronghold of the kings of Dumnonia - a kingdom comprising Cornwall, Devon and parts of Somerset. During this time a large defensive ditch was dug, effectively cutting off access to the headland, and helping give Tintagel its name - Din Tagell, the Fortress of the Narrow Entrance.
In 1233, Richard, Earl of Cornwall, acquired Tintagel and built a castle on the headland. The location was not ideal for building a castle and the area had no strategic value, so we have to presume that Richard probably wanted to associate himself with the already popular Arthurian legends. Later Earls of Cornwall made little use of the castle, leaving it in the care of a constable, and by the late 15th century the castle was already in ruins.