Fathers of the Church, collective name for the Christian writers of early times whose work is considered generally orthodox. A convenient definition includes all such writers up to and including St. Gregory I (St. Gregory the Great) in the West and St. John of Damascus in the East (see patristic literature). There are several conventional groupings of the Fathers of the Church. One of these is the Apostolic Fathers, usually considered to include the authors of the Didache, of the Epistles of Clement, of the Epistles of Ignatius of Antioch, and of the Shepherd of Hermas. In an ancient category of honor eight Doctors of the Church are set apart; the Four Doctors of the Greek Church are St. Basil the Great, St. Gregory Nazianzen, St. John Chrysostom, and St. Athanasius; the Four Doctors of the Latin Church are St. Ambrose, St. Jerome, St. Augustine, and St. Gregory the Great. Since the 16th cent., the title Doctor of the Church has also been given by the Roman Catholic Church to later doctrinal writers, including St. Thomas Aquinas, St. Bonaventura, St. Anselm, St. Bernard of Clairvaux, St. John of the Cross, St. Theresa of Avila, and St. Catherine of Siena.