Before the Norman invasion of Wales, the Shirenewton area formed part of the forest of Wentwood (). At the time of the Domesday Book, it was part of the lands at Caldicot which were held by Durand, the Sheriff of Gloucester. Durand and his successor as sheriff, his nephew Walter FitzRoger also known as Walter de Gloucester, had part of the forest cleared around the year 1100, and established a small settlement which was known as Sheriff's Newton (or New Town) or, in Latin, Nova Villa. The manor then became known as Caldecot-cum-Newton, and in some documents the village was called Newton Netherwent. Netherwent is the English name given to the Welsh cantref of Gwent-is-coed (Gwent beneath the wood, i.e. Wentwood), with -went deriving from the Roman town of Venta which became Caerwent. The name Sheriff's Newton became contracted over the years into Shirenewton.