urch with the kingdom of God, and claimed that it was
supreme over all the nations of the earth, which make up the _civitas
terrena_ or earthly state. Augustine's theory was ultimately accepted
everywhere in the West, and thus the Church of the middle ages was
regarded not only as the sole ark of salvation, but also as the ultimate
authority, moral, intellectual and political. Upon this doctrine was
built, not by Augustine himself but by others who came after him, the
structure of the papacy, the bishop of Rome being finally recognized as
the head under Christ of the _civitas Dei_, and so the supreme organ of
divine authority on earth (see PAPACY and POPE).

_Historical Sources of the First Period._--These are of the same
general character for Church history as for general history--on the
one hand monumental, on the other hand documentary. Among the
monuments are churches, catacombs, tombs and inscriptions of
various kinds, few antedating the 3rd century, and none adding
greatly to the knowledge gained from documentary sources (see
De Rossi, _Roma sotteranea_, 1864 ff., and its English abridgment
by Northcote and Brownlow, 1870; Andre Perate, _L'Archeologie
chretienne_, 1892; W. Lowrie, _Monuments of the Early Church_, 1901,
with good bibliography). The documents comprise imperial edicts,
rescripts, &c, liturgies, acts of councils, decretals and letters of
bishops, references in contemporary heathen writings, and above all
the works of the Church Fathers. Written sources from the 1st and
2nd centuries are relatively few, comprising, in addition to some
scattered allusions by outsiders, the New Testament, the Apostolic
Fathers, the Greek Apologists, Clement of Alexandria, the old
Catholic Fathers (Irenaeus, Tertullian and Hippolytus) and a few
Gnostic fragments. For the 3rd, and especially the 4th and following
centuries, the writers are much more numerous; for instance, in the
East, Origen and his disciples, and later Eusebius of Caesarea,
Athanasius, Apollinaris, Basil and the two Gregories, Cyril of
Jerusalem, Epiphanius, Chrysostom, Ephraim the Syrian, Cyril of
Alexandria, Pseudo-Dionysius; in the West, Novatian, Cyprian,
Commodian, Arnobius, Lactantius, Hilary, Ambrose, Rufinus,
Jerome, Augustine, Prosper, Leo the Great, Cassian, Vincent of
Lerins, Faustus, Gennadius, Ennodius, Avitus, Caesarius, Fulgentius
and many others.

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