William d'Aubigny

William d'Aubigny of Belvoir was the son of the Magna Carta surety of the same name, who had held Rochester Castle against King John in the terrible siege of 1215. William held Belvoir after his father and died in 1247 leaving only daughters, of whom Isabel carried the castle to the Ros family - who were themselves of surety stock, so that Belvoir passed from one charter family to another.