Was the NT church the universal church? Yes it was. It was based on faith in Christ and Christ alone.
However, what we've seen over time is the deportation from that. Roman Catholicism came about around 200-300 AD.
Rome has advanced so many false teachings it's hard to identify them all. Roman Catholicism is essentially Jesus+Mary+Works+Baptism+, etc+etc.
We Catholics don't rely so much on the accuracy* of the things taught us; but on the AUTHORITY of those that teach them TO us.
--Catholic_Wannabe_Dude(Hail Mary: who holds us Catholics in complete unity)
*Romans 14:1
Accept the one whose faith is weak, without quarreling over disputable matters.