| Term | Definition |
| Pope Clement I | 4th Pope, Lived in the first century, died 100AD |
| Ignatius of Antioch | Coined the term Catholic Church, Describes the Church in Rome as the one founded by Peter and Paul |
| St Polycarp | Learned Christianity from Apostle John, martyr, did not burn in fire then was stabbed |
| St Justin martyr | Martyred for refusing to make sacrifices to toher gods, an apologist |
| Irenaeus of Lyons | wrote against Heresies, Tomb destroyed by Calvinists |
| St Alexander of Alexandria | opposed the Arian Heresy started by Arius, Heresy taught that Jesus was not God |
| St. Ambrose | Was a political govenor, Within a week he was baptized, ordained, and appointed Bishop |
| St Jerome | Known for his translating the Bible into Latin, wrote The Perpetual Virginity of Blessed Mary |
| St Augustine | A convert who is the son of St. Monica, was a big sinner before converting, became the Bishop of Hippo |
| Pope Leo, the Great | Pope during conquests of Attila the Hun, stopped Attila from invading Rome |
| Cyprian of Carthage | wrote many epistles about Christ and the Church, focused heavily on the unity of the Church |