The date of the birth of Tatian is not known, but he died around 180. Tatian originally came from Assyria in Upper Mesopotamia, and was well educated in Greek learning, even though he eventually despised it. He spent a long time travelling as a wandering sophist and eventually came to Rome around the year 150 where he became a Christian. He became a pupil of Justin Martyr, following his teaching.
While working with Justin, Tatian wrote a number of apologetic works defending Christianity, dedicated to the emperor but intended to be read by the general public. In these, he answered accusations against Christianity, and exposed the intellectual weaknesses of paganism. Most of these works are now lost, but are mentioned by Eusebius. Their titles included, ‘On Animals’, ‘On Demons’, ‘On Perfection’, and the ‘Book of Problems’.
There are two works still in existence. The first is his ‘Address to the Greeks’, which was a defence of Christian ideas and life. This was a fairly orthodox presentation of Christian apologetics, showing the superiority of Christianity over Greek philosophy and culture. It is written in a harsh and bitter style, denouncing other views. It does not describe much about the person of Christ, his incarnation, or his atonement for sins.
The second is his 'Diatesseron', which is a harmony of the four gospels, giving the life of Christ. It was widely used by the Syrian church until the fifth century, particularly for educational and liturgical purposes. Its use was forbidden after Tatian was denounced as a heretic in the early 400's. However, it confirmed the exclusivity of the four gospels.
After the death of Justin around 165, Tatian left Rome and founded the sect of the Encratites, meaning ‘self-controlled’, and returned to Mesopotamia, living in Edessa, in the far eastern parts of the Roman Empire. The teaching of the Encratites was heavily Gnostic, believing that physical matter was evil. They insisted on many severely ascetic practices, including the prohibition of marriage, and abstinence from eating meat. The teaching combined the aeons of the Valentinius and the distinction between the God of justice and the God of love characteristic of the teaching of Marcion.
Address to the Greeks