The largest and most well known is the Latin Church, with more than 1 billion members worldwide.
Relatively small in terms of adherents compared to the Latin Church, are the 23 self-governing Eastern Catholic Churches with a combined membership of 17.3 million as of 2010 The Latin Church is governed by the pope and diocesan bishops directly appointed by him.
There are three levels of clergy, the episcopate, composed of bishops who hold jurisdiction over a geographic area called a diocese or eparchy; the presbyterate, composed of priests ordained by bishops and who work in local diocese or religious orders; and the diaconate, composed of deacons who assist bishops and priests in a variety of ministerial roles.
Ultimately leading the entire Catholic Church is the Bishop of Rome, commonly called the pope, whose jurisdiction is called the Holy See.
The Catholic Church shared communion with the Eastern Orthodox Church until the East–West Schism in 1054, disputing particularly the authority of the Pope, as well as with the Oriental Orthodox churches prior to the Chalcedonian schism in 451 over differences in Christology.
Catholics live all over the world through missions, diaspora, and conversions.
The Catholic Church continues these traditions, through constituent autonomous particular churches, also known as "churches sui iuris" (Latin: ").
Headed by the Bishop of Rome, known as the Pope, the church's doctrines are summarised in the Nicene Creed.
Its central administration, the Holy See, is in the Vatican City, enclaved within Rome, Italy.
The Virgin Mary is venerated in the Catholic Church as Mother of God and Queen of Heaven, honoured in dogmas and devotions.
Its teaching includes sanctification through faith and evangelisation of the Gospel and Catholic social teaching, which emphasises support for the sick, the poor, and the afflicted through the corporal and spiritual works of mercy.