There is no "Roman" Catholic Church: Roman is an epithet first commonly used in England after the protestant revolt to describe the Catholic Church. It is rarely used by the Catholic Church. The Chaldean Catholic Church is part of the Catholic Church.

The Roman Catholic Church is a type of Christian Church.

You would use the phrase Roman Catholic Church as a noun, because it's a name. For example, "The Roman Catholic Church is headquarted in Vatacin City" or "John is a member of the Roman Catholic Church". Tip: there is no Roman Catholic Church. It is the Catholic Church.

No, there is no Saint Corinne, nor for that matter is there a "Roman Catholic Church". It's just Catholic, not Roman Catholic. Roman is an epithet first commonly used in England after the protestant revolt to describe the Catholic Church. It is never used by the official Catholic Church.

the Eastern Orthodox Church and the Roman Catholic Church