Well, almost correct...Constantine promoted a religious sect that claimed to be Christianity but was the beginning of the Catholic religion...
It was a win-win for the new Catholic religion since Constantine forced his armed forces to get baptized and become Catholics whether they wanted to or not...
This gave the new religion the massive power to overthrow by force those Christians who died holding their scriptures and refusing to bow down to the new state-religion...
And thank God, groups of those Christians and copies of those scriptures perservered thru-out history to this day...
Most Christians in the time of Constantine would today be called Eastern Orthodox, not Roman Catholic.
Constantine brought them together at Nicaea and required them to develop a single doctrine which all must subscribe to or be treated as heretics.
The bishops obliged, the majority ruled, and minority heretics fell into the same category as pagans: outlawed with property confiscated for the Emperor's treasury.
For on thing: it was the Emperor's alternative to raising everyone's taxes to finance his great imperial projects.