Columbia subject headings:
Harvard subject headings:
Apologetics--Early works to 1800
Apologetics--History--Early church, ca. 30-600
Theology--Early works to 1800
Princeton subject headings:
Apologetics--Early works to 1800.
Greece--Civilization--Early works to 1800.
Philosophy and religion--Early works to 1800.
Philosophy, Ancient.
Theology, Doctrinal--Early works to 1800.