pontifex

Latin pontifex combined pons (bridge) and facere (to make). The Pontifex Maximus was the chief bridge-builder — and the most important religious official in Rome. The College of Pontiffs, which he headed, oversaw Roman state religion: sacrifices, sacred calendars, priestly duties, and the regulation of religious law. The etymology is disputed: some scholars take it literally (early Roman priest-engineers who built the original Tiber bridges); others suggest it meant something like 'path-maker' or 'way-maker' to the gods.

Julius Caesar held the title of Pontifex Maximus from 63 BCE until his death. Augustus made it a permanent part of the imperial title, and every Roman emperor from Augustus to Gratian (who refused it as a pagan title in 382 CE) bore the title. The Pontifex Maximus was the symbolic head of Roman state religion for nearly five centuries.

When Christianity became the official religion of Rome, the title migrated. The Bishop of Rome — the Pope — adopted Pontifex Maximus as a claim to supreme religious authority, the title passing from pagan Rome's chief priest to Christianity's most powerful churchman. The transfer happened gradually in the 4th and 5th centuries.

Today 'pontiff' refers almost exclusively to the Pope. Pontifex Maximus still appears in Vatican Latin. The bridge-builder who managed Rome's sacrifices still stands at the center of the world's largest Christian denomination, the etymology intact under layers of theological claim.