Yup, you’re referring to the Pentarchy:
"Pentarchy is a model of Church organization formulated in the laws of Emperor Justinian I (527–565) of the Roman Empire. In this model, the Christian church is governed by the heads (patriarchs) of the five major episcopal sees of the Roman Empire: Rome, Constantinople, Alexandria, Antioch, and Jerusalem.”
Which interestingly still kinda coincides with the modern day:
Rome: Roman Catholic Church
Constantinople: Eastern Orthodox Church (Greek Orthodox, Russian Orthodox, etc)
Alexandria: Coptic Orthodox Church of Egypt
Antioch: Orthodox Churches of Syria and India
Jerusalem: This ones very complicated lol
The original 3 church centers were Alexandria, Rome, and Antioch
