Beside persecutions by the Roman empire, one major issue that occupied the early church is the alternative teachings. So today we learnt about these teachings: Marcionism, Gnosticism, and Manichaeism (and a little bit about Montanism). Then we learnt about the church fathers who dealt with these teachings: Justin Martyr (100-165), Irenaeus of Lyons (115-202 — cicit KTB-nya Yesus: Yesus, Yohanes, Polikarpus, Irenaeus), Clement of Alexandria (150-215), Hippolytus (170-235), and Origen of Alexandria (186-254).
They are usually called Ante-Nicene Fathers, since they didn’t have direct connection with the apostles themselves (those who had would be called the Apostolic Fathers) and they preceded the Council of Nicaea (325) — hence, Ante-Nicene (ante- means before). Sometimes they are called the Apologists also, since they spent a lot of efforts to to defend the Christian faith; be it against the Romans or against the so-called heretics.
Some important developments during this period would be: (1) early efforts to formulate orthodoxy, partly because of the alternative teachings and groups, and (2) efforts to synthesize Christian faith with Greek philosophy, with various results (e.g., orthodox Alexandrian school and heterodox Gnostics).
(one interesting story that the lecturer told us: allegorical interpretation of the parable of the good Samaritan — guess by who?)