If Sittingbourne did exist at any of the above locations, it would not have been known as Sittingbourne as such. Up to at least the twelfth century the area we now know as Sittingbourne was a part of the Royal manor of Milton, a town that was the port and market centre for the surrounding area. Indeed, when William the Conqueror compiled the Domesday Book in 1068, Sittingbourne is not even mentioned.
/ The History of Sittingbourne
/ Sittingbourne today, its origins