 In Graham Robb's book "The Ancient Paths" there is a suggestion that Welwyn lay on a late-Celtic highway running in the direction of the summer solstice angle straight from Bury St Edmunds to Salisbury via the Catuvellauni headquarters at Verlamion outside modern-day St Albans.Separately, it can be shown that the line of the Roman road through Welwyn (see below) is in a direct alignment with the pre-Roman Belgic tribal centres of Verlamion (for the Catuvellauni) and Venta Icenorum for the Iceni tribe.Following the Roman invasion, Welwyn was settled by the Romans.