The earliest reference to the site was in the Domesday Book survey of 1086. The 'Minster' of Southwark seems to be under the control of Bishop Odo of Bayeux (William the Conqueror's half-brother). Its early history is obscure. A Saxon minster (a teaching church) served a south Thames area. In 1106, Henry I's reign, the latter became an Augustinian Priory: Norman stonework can still be seen, and Thomas Becket preached here before departing to Canterbury, days before his murder in 1170.