Tertullian

Tertullian (Latin: Quintus Septimius Florens Tertullianus; c. AD 155 – c. 220) was a prolific early Christian author from Carthage in the Roman province of Africa. He was the first Christian author to produce an extensive corpus of Latin Christian literature and was an early Christian apologist and a polemicist against what he viewed as heresy, including Gnosticism.

Tertullian was the first theologian to write in Latin, and so has been called "the father of Latin Christianity", as well as "the founder of Western [Christian] theology". He is perhaps most famous for being the first writer in Latin known to use the term trinity (Latin: trinitas).

Tertullian enunciated new theological concepts and advanced the development of early Church doctrine. However, some of his teachings, such as the subordination of the Son and Spirit to the Father, were later rejected by the Catholic Church. Tertullian later joined the Montanist sect, but today most scholars reject the assertion that he left the mainstream church or was excommunicated.