Cilgerran Castle as part of CADW's Magna Carta Trail in Wales. Catherine Collins ...castle warden and procurer of the funds for both mine and Caroline Gregson's sculpture at the Chepstow Castle site, was very persuasive in having a Knight to represent William Marshal, Earl of Pembroke and the Greatest Knight who was responsible for bringing the Magna Carta into existence. Quite a formidable and strong character seemed to demand a slightly larger than life willow form. He is built around a metal framework and built up in layers of body, tunic, chainmail and sircoat with a striking metal sword. I think he looks the part taking command in his castle in the beautiful village of Cilgerran cilgerran.inforan overlooking the Teifi Gorge in Pembrokeshire. Splendid. We hope he will remain for sometime but it is best to visit him while he is in his prime.