The Western Church is now a tightly organized vast portion of the Catholic Church.  In its origins, it included the foundation of many, diverse local Churches­–Ambrosian, Irish, French (Gallican), Spanish, and Slavic (Cyril and Methodius were the founders, using old Slavic, rather than Latin), each under the authority of the Holy Father, the Bishop of Rome. The formation of the Western Church was, therefore, very similar to that of the Eastern Church.

The title “Western Church” developed in a comparable way to the title “Eastern Church.” These titles initially indicated places of origin. The Western Church included all those Churches west of Rome; whereas, the Eastern Churches included all those Churches east of Rome.

The Western Church uses Latin liturgies and has its own distinctive Canon Law (known as the Code of Canon Law). It is in union with Rome and it is often called simply, the “Latin Rite” or the “Roman Rite” although it embraces several Rites:

  1. The Latin or Roman Rite and its derivatives, such as the Ambrosian and Mozarabic liturgies, and
  2. The Rites of some religious orders, including Carmelite Rite, the Dominican Rite, and the Carthusian Rite.

It is also called: the Church of Rome, the Patriarchate of the West or the Roman Catholic Church.

The term “Roman Catholic Church” may be used in two ways; one is limited and the other is all-encompassing. First, it may be used in a limited way, as noted above, to denote a Western Church or Western Churches united with the Bishop of Rome in his capacity as local Bishop of Rome, * not in his capacity as Vicar of Christ (that is, the Head of the Universal Church). **

Second, in an all-encompassing way, the term “Roman Catholic Church” may be used to denote the Universal Church united in obedience to the Vicar of Christ, the successor of Saint Peter, who also happens to be the local Bishop of Rome and head of various groups of Catholic Churches in the West. When we use the term Roman Catholic Church to designate the Universal Church, then it designates all those Churches, East as well as West, that are united with the Vicar of Christ. 

In the Universal Church, Eastern Rite Churches are not obliged to call themselves “Roman” Catholic if they reserve this term to designate their relationship with Western Catholics. Eastern Catholics commonly use the term “Roman Catholic” to designate a local Church or groups of local Churches in the Western Rite who are subject to the Bishop of Rome. Eastern Catholics too, are subject to their local Bishop and are united in obedience to the Vicar of Christ. Eastern Catholics, then, in confessing their unity in the one Church via obedience to the Vicar of Christ in Rome are genuine “Roman Catholics,” but are not obliged to call themselves “Roman” Catholic to confess this. Schismatic Churches in the East, on return to unity with the Universal Church, commonly call themselves “United,” that is, united with the Pope in obedience to Rome.  United in the East is more or less the equivalent to Roman Catholic in the West.

*When it is said that you are subject to the Bishop of Rome in his capacity as local Bishop of Rome, this means you are in the Latin Church, using liturgical traditions and customs derived principally from Rome.

**When it is said that you are subject to the Vicar of Christ in his capacity as Vicar, this means you may be in the Latin Church or the Eastern Catholic Church, following their customs for ceremonies, liturgical worship, administration of the Sacraments and Code of Canon Law, but you are united in obedience to the Vicar of Christ and are part of the one true Catholic Church. (For Advanced Course lessons 19 and 23.)