Nestorius (d. c. 451) was one of the principle representatives of the Antiochene (from Antioch) school of theology. He became the patriarch of Constantinople in 428. His emphatic stress on the humanity of Christ led his critics to charge him with having denied Christ's divinity. He was charged with heresy forhis famous refusal to grant Mary the title "Theotokos" (Mother of God). Since few of Nestorius' writings are extant, what follows is a selection from a history of the church compiled by an individual named Socrates which reflects accurately what is known about the situation at the time. This is taken from McGrath's Christian Theology Reader.

Now [Nestorius] had as a colleague the presbyter Anastasius, who he had brought from Antioch. He had high regard for him, and consulted him over many matters. Anastasius was preaching one day in church, and said, "Let no one call Mary the Mother of God (Theotokos): for Mary was only a human being, and it is impossible that God should be born of a human being." This caused a great scandal, and caused distress to both the clergy and the laity, as they had been taught up to this point to acknolwege Christ as God, and not to separate his humanity from his divinity on account of the economy [of salvation]. . . . While great offence was taken in the church at what was proclaimed in this way, Nestorius, who was eager to establish Anastasius' proposition – for he did not wish to have someone who he so highly esteemed found guilty of blasphemy – continually kept on giving instruction in church on this subject. He adopted a controversial attitude, and totally rejected the term Theotokos. The controversy on the matter was taken one way by some and another way by others, with the result that the ensuing discussion divided the church, and began to look like people fighting in the dark, with everyone coming out with the most confused and contradictory assertions. Nestorius acquired the popular reputation of asserting that the Lord was nothing more than a human being, and attempting to impose the teaching of Paul of Samosata and Photinus on the church. This led to such a great outcry that it was thought necessary to convene a general council to rule on the matter in dispute. Having myself studied the writings of Nestorius, I have found him to be an unlearned man and shall express quite frankly my own views about him. . . . I cannot concede that he was a follower of either Paul of Samosata of of Photinus, or that he ever said that the Lord was nothing more than a human being. However, he seemd scared of the term Theotokos, as though it were some terrible phantom. The fact is, the groundless alarm he showed on this subject just showed up his extreme ignorance: for being a man of natural ability as a speaker, he was considered well educated, but in reality he was disgracefully illiterate. . . .