The Roman Catholic Church was the primary church of the Middle Ages.
The Roman Catholic Church can be dated back to about the late 17th century (1650+). Its full name is the Romanian Greek Catholic church, due to the peoples that brought it into existence. The Roman Catholic church was founded after the Austro-Hungarian Empire assumed control over Transylvania when the native peoples evacuated. They encouraged the predominantly Eastern Orthodox believers to join Rome, primarily by denying full civil rights to those who didn't align themselves. An agreement was reached between Orthodoxy and Catholic leaders in 1698, and approved two years later, at which point the church was actually brought into existence as the primary church of the Ages.
The Romanian Greek Catholic Church is still alive and active today and claims over 700,000 members.