He was a soldier in the Roman army and, according to the venerable Bede, was brought to faith in Christ by a fugitive priest to whom he gave shelter. The saint exchanged clothes with the priest, allowing him to escape and ensuring his own martyrdom. Some writers, including St Bede, place his martyrdom during the reign of Diocletian (286-303).

Saint Alban's tomb was venerated as early as 429 by St Germanus of Auxerre. The town of Verulamium is either his home town or the place of his martyrdom; near it a monastery was founded, around which grew the English town of St Albans.