One theory suggests that Lucius Artorius Castus, a Roman military commander who served in Britain in the late 2nd century or early 3rd century, was a prototype of Arthur. Artorius is known from two inscriptions that give details about his service. After a long career as a centurion in the Roman army, he was promoted to prefect of Legio VI Victrix, a legion headquartered in Eboracum (present-day York, England). He later commanded two British legions on an expedition against either the Armoricans (in present-day Brittany) or the Armenians. He subsequently became civilian governor of Liburnia in modern Croatia, where he died.