The answer
The word 'See' means the Seat or the authority, jurisdiction, and governmental functions associated with the papacy.When the Emperor Constantine established the city of Byzantium, or Constantinople, as the new capital of the Roman Empire, replacing Rome, the bishop of Byzantium became very prominent. The See of Constantinople joined the first four Sees in the fourth century.
Answered by His Eminence Metropolitan Youssef (opens in a new tab)