 The site is likely to have been of strategic value, having a well, standing on high ground above the Somborne valley, and lying a short distance from the Roman road from Winchester to Sarum.Its builder was the powerful Henry de Blois, a grandson of William I of England, and the younger brother of King Stephen.Henry de Blois was the Bishop of Winchester from 1129 until his death 1171, a prolific builder (including of Wolvesey Palace, the bishop's palace in Winchester, and of a number of castles), and one of the most powerful figures of his day in the English kingdom.