Sudbury's history dates back into the age of the Saxons. The town's earliest mention is in 799 AD, when Aelfhun, Bishop of Dunwich, died in the town. The "Anglo-Saxon Chronicle" records the town as "Suthberie" ("south-borough"), presumed to distinguish it from Norwich or Bury St Edmunds, to the north, and ca. 995 is recorded as "Suthbyrig". The town is also mentioned in the Domesday Book of 1086, as a market town where the local people came to barter their goods. The market was established in 1009. During this period the town was surrounded by a defensive ditch and a diverted section of the River Stour.