Amphibalus is a venerated early Christian priest said to have converted Saint Alban to Christianity. He occupied a place in British hagiography almost as revered as Alban himself. According to many hagiographical accounts, including those of Gildas, Bede, Geoffrey of Monmouth, and Matthew of Paris, Amphibalus was a Roman Christian fleeing religious persecution under Emperor Diocletian. Amphibalus was offered shelter by Alban in the Roman city of Verulamium, in modern-day England. Alban was so impressed with the priest's faith and teaching that he began to emulate him in worship, and eventually became a Christian himself. When Roman soldiers came to seize Amphibalus, Alban put on Amphibalus' robes and was punished in his place. According to Matthew Paris, after Alban's martyrdom, the Romans eventually caught and martyred Amphibalus as well.

Redbourn is a village and civil parish in Hertfordshire, England, three miles (4.8 km) from Harpenden, four miles (6.4 km) from St Albans and five miles (8.0 km) from Hemel Hempstead. The civil parish had a population of 6,913 according to the 2011 Census.