Regnum

REGNUM a town of the Belgae in the S. of Britannia Romana, and seemingly a place of some importance, since there was a particular road to it. (Itin. Ant. p. 477.) Camden (p. 133) identifies it with Ringwoodin Hampshire. Horsley, on the contrary (p. 441), conjectures it to have been Chichester; but, though Roman antiquities have been found at Chichester, its situation does not suit the distances given in the Itinerary.
[T.H.D]