The substantial and well preserved castle and church were established by the invading Normans in 1106. The earliest castle on the site was a typical Norman motte and bailey design that was made of earth and timber. The 13th century re-design was commissioned by Edward I Longshanks as a strategic part of his 'Ring of Steel' oppression against the Welsh. At the time of the stone castle's creation, Kidwelly benefited from the latest strategic military thinking in castle design. It had a concentric design with one circuit of defensive walls set within another to allow the castle to be held even if the outer wall should fall. The great gatehouse was begun late in the 14th century but it was not completed until 1422, somewhat due to the Welsh rebel Owain Glyndŵr’s efforts to reclaim Welsh independence.