Tertullian
The first major Christian theologian to write in Latin and the founder of Latin Christian theological vocabulary.
Tertullian of Carthage was the first major Christian theologian to write in Latin and is the founding figure of Latin Christian theological vocabulary. Born around 155 AD in Carthage in Roman North Africa (modern Tunisia), he received an excellent classical education and worked as a lawyer or rhetorician before converting to Christianity around 197 AD. He wrote prolifically over the next two decades, producing more than thirty surviving works on Christian doctrine, ethics, prayer, and apologetics. His theological vocabulary shaped Latin Christianity for eighteen centuries: he coined or popularized the Latin theological terms Trinitas (Trinity), persona (person), substantia (substance), sacramentum (sacrament), and satisfactio (satisfaction), among many others. His Apology (c. 197 AD) is one of the most powerful defenses of Christianity from the period of Roman persecution. His De Oratione (On Prayer, c. 200 AD) is the earliest surviving sustained Christian treatise on prayer and documents the actual prayer practices of early Christians (standing posture, hands extended, the Lord's Prayer as foundational). Late in his life, however, Tertullian joined the New Prophecy movement (later called Montanism), a charismatic Christian movement that the broader Church judged heretical, and for this reason he was never formally canonized as a saint despite the enormous influence of his pre-Montanist writings on all subsequent Christian theology. His pre-Montanist works remain foundational to Christian theology in every tradition.