Aristobulus of Britannia was an early Christian missionary and priest who is traditionally recognized as the first bishop of Roman Britain. Identified by early church writers as one of the Seventy Disciples, he is believed to have been a companion of the Apostle Paul. Some traditions suggest he was the brother of Barnabas and traveled through northern Hispania to preach to the Celtiberians before reaching the British Isles, where he established the early Christian community.