The Church Fathers, Early Church Fathers, Christian Fathers, or Fathers of the Church were ancient and influential Christian theologians and writers who established the intellectual and doctrinal foundations of Christianity. The historical period in which they worked became known as the Patristic Era and spans approximately from the late 1st to mid-8th centuries, flourishing in particular during the 4th and 5th centuries, when Christianity was in the process of establishing itself as the state church of the Roman Empire.
The Church Fathers, an 11th-century Kievan Rus' miniature from Svyatoslav's miscellany
St. Athanasius, depicted with a gospel book, an iconographic symbol used mostly for priests and bishops as preachers of the gospel
The Four Great Latin Church Fathers by Jacob Jordaens
Print of Jerome in his study. Preserved in the Ghent University Library.
Patristics or patrology is the study of the early Christian writers who are designated Church Fathers. The names derive from the combined forms of Latin pater and Greek πᾰτήρ (father). The period of the Church Fathers, commonly called the Patristic era, is generally considered to run from the end of New Testament times or end of the Apostolic Age to either AD 451 or to the Second Council of Nicaea in 787.
Irenaeus
Tertullian
Augustine
Volumes from Philip Schaff's The Nicene and Post-Nicene Fathers.