Caernarfon Castle ? often anglicised as Carnarvon Castle or Caernarvon Castle ? is a medieval fortress in Caernarfon, Gwynedd, north-west Wales cared for by Cadw, the Welsh Government's historic environment service. It was a motte-and-bailey castle from the late 11th century until 1283 when King Edward I of England began to replace it with the current stone structure. Collectible framed postage stamp