In 1102, as a matter of political expediency, Henry I entrusted the Welsh territory (or commote) of Cydweli, along with Ystrad Tywi and Gower, to Hywel ap Goronwy, a Welshman who had risen to favour at a time when the king was threatened by the powerful Montgomery family. Once this threat had subsided and following Hywel's murder in 1106, Henry reestablished Norman control by installing his trusted advisor, Roger, bishop of Salisbury (d. 1139), as lord of Kidwelly. The building of the castle and the town probably started soon after.