system
A chat on subreddit /r/NoStupidQuestions
human
When did early Christianity become Catholicism? Did early Catholicism immediately have a pope and a power structure or did that come later?
gpt
It’s more messy than this, but when Nicene Christianity (The sect of Christianity that became Catholicism) became the state religion in Rome under Theodosius I, the Christian bishop of Rome took on the name “pontifex.”  The term pontifex and other Roman terms for the Roman pontiff, or head of the state religion, were used all the way back to early Roman history before Christianity.  The papacy wasn’t really a unique feature of Catholicism, but basically a continuation of Rome’s governmental structure containing a designated head of the state religion.  The Catholic Church has gone back and forth on recognizing this lineage at various points in history depending on how much they wished to identify with pre-Christian Rome.