Catholic (from Greek: καθολικός, translit. katholikos, lit. 'universal') was first used to describe the church in the early 2nd century. The first known use of the phrase "the catholic church" (καθολικὴ ἐκκλησία he katholike ekklesia) occurred in the letter written about 110 AD from Saint Ignatius of Antioch to the Smyrnaeans.[note 2] In the Catechetical Lectures (c. 350) of Saint Cyril of Jerusalem, the name "Catholic Church" was used to distinguish it from other groups that also called themselves "the church". The "Catholic" notion was further stressed in the edict De fide Catolica issued 380 by Theodosius I, the last emperor to rule over both the eastern and the western halves of the Roman Empire, when establishing the state church of the Roman Empire.
Since the East–West Schism of 1054, the Eastern Church has taken the adjective "Orthodox" as its distinctive epithet (however, its official name continues to be the "Orthodox Catholic Church") and the Western Church in communion with the Holy See has similarly taken "Catholic", keeping that description also after the Protestant Reformation of the 16th century, when those who ceased to be in communion became known as "Protestants".
While the "Roman Church" has been used to describe the pope's Diocese of Rome since the Fall of the Western Roman Empire and into the Early Middle Ages (6th–10th century), the "Roman Catholic Church" has been applied to the whole church in English language since the Protestant Reformation in the late 16th century. "Roman Catholic" has occasionally appeared also in documents produced both by the Holy See,[note 3] notably applied to certain national episcopal conferences, and local dioceses.[note 4]
The name "Catholic Church" for the whole church is used in the Catechism of the Catholic Church (1990), and the Code of Canon Law (1983). It was equivally applied in the documents of the Second Vatican Council (1962–1965), the First Vatican Council (1869–1870), the Council of Trent (1545–1563), and numerous other official documents.