Ambrosius Aurelianus
In his book "Historia Brittonum", Nennius affirms that "The reign of Vortigern, and the fight between Vitalinus and Ambrosius in Guoloppum, the Battle of Guoloph, are separated by twelve years". The battle is thought to have been part of the long rivalry between rival British kings Vortigern and Ambrosius Aurelianus for control of southern Britain in the wake of the Roman withdrawal in 410.