Amphibalus was the Christian priest that St Alban sheltered from persecution. Tradition says the priest was later martyred at Redbourn.

This shrine base was built for his relics in the middle ages but was smashed into pieces at the Reformation, as was St Albans shrine. These pieces were rediscovered in 1872. In 2020 this shrine was cleaned and restored with new carvings to replace some of its lost stones.

St Albans is the only Cathedral in the country to house two medieval pedestal shrines - belonging to St Alban and St Amphibalus.