Civitas Belgarum
The Civitas Belgarum was in the southwest of the Roman province of Britain . Their main town was Venta Belgarum , today's Winchester . The civitas arose under Roman rule from the empire of the Celtic Atrebats , whereby the civitas was a Roman creation and has only limited connection with the Celtic kingdom.
Claudius Ptolemy mentions two other places in the Belgae area, Aquae Calidae (hot spring spa), which is Aquae Sulis (Bath), and a previously unidentified place called Iscalis .
Another important place of the civitas was Clausentum , a port in what is now Southampton . The Isle of Wight was also part of it.