Christian apologetics is a branch of Christian theology that defends Christianity.

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.