The original castle seems to have been a sub-rectangular/oval enclosure overlooking the River Tawe on the east, surrounded on the north, west and south sides by a larger sub-rectangular outer bailey. The inner bailey probably contained a motte but the other view is that it was a ring work. The new castle was attacked by the Welsh in 1116 but the inner castle held. By then the castle had lost its military importance. It is not known whether it fell to allies of Owain Glyndŵr early in the 15th century.