Unconvinced, your knowledge of the development of the Roman Catholic Church is sadly lacking. The RCC became an organized hierarchy after 325 A.D. You can more accurately place the date as 381 A.D. after Constantine established 5 Patriarchies to govern the Christian community. Each Patriarch was headed by a bishop and each had equal authority.
It was not until Boniface III (through political influence) was given the title Vicar of Christ in the 7th century that Rome gained supremacy (at least in their eyes). The actual center of Christianity was Constantinople until it was sacked during the Crusades, which John Paul II has publicly apologized for with the hope of bringing the Orthodoz churches back into the fold of the RCC. The first major doctrinal split came in the 5th century when the Coptic Orthodox Church refused to accept a church councils declaration about the nature of Christ.
The word "catholic" was used prior to the 4th century for all Christians as the word means "universal". If you really want to know what makes a person a Roman Catholic read this: http://www.scborromeo.org/ccc.htm