Source: https://etimasthe.com/2017/11/27/some-lessons-from-the-diatessaron-of-tatian-part-1/
Timestamp: 2019-04-25 03:51:26+00:00

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I recently finished reading an English translation of a second-century Christian work, the Diatessaron, by Tatian the Assyrian. In a new series of posts we look at twelve things the Diatessaron shows us about early Christianity and the New Testament Gospels.
The Diatessaron is the world’s first harmony, or composite, of the four Gospels (Matthew, Mark, Luke and John). It was compiled by Tatian, a native of Syria (more on him later), around the middle of the 2nd century A.D.
Scholars are unsure whether Tatian originally wrote it in Greek (the language of the New Testament) or in his native Syriac. In any case the Diatessaron was accorded the highest possible esteem in the Syriac Church for several centuries, even being used in place of the four Gospels.
After around three centuries of such usage in the Syriac churches, eventually in the fifth century successful efforts were made to suppress it in favour of the four distinct Gospels in use throughout the rest of the Christian Church. Hence Rabbula, bishop of Edessa (d. 435 A.D.), decreed, “Let the presbyters and deacons give heed that in all the churches there be provided and read a copy of the Distinct Gospel,” that is, the four Gospels as opposed to the ‘mixed’ Gospel. Theodoret, bishop of Cyrus during the same period, removed over two hundred copies of the Diatessaron which he found in his diocese, replacing them with the four Gospels.
No Syriac copy of the Diatessaron is known to survive, although we do have portions of the Syriac preserved in a commentary on it by Ephraem the Syrian (c. 306—373 A.D.) which was rediscovered in its original Syriac in 1957.
an Arabic translation of the Diatessaron preserved in two manuscripts, the Vatican manuscript dating from approximately the twelfth century, and the Borgian manuscript dating from around the fourteenth.
One scholar has estimated that the Diatessaron contains 50% of Mark’s Gospel, 66% of Luke’s, 76.5% of Matthew’s, and 96% of John’s Gospel: meaning that the work contains about 73% of the total material in the four Gospels.
The translation on which this series of posts is based is the nineteenth-century translation by Rev. Hope W. Hogg, in the Ante-Nicene Fathers Vol. X, which is based on the two Arabic manuscripts.
Tatian (c. 120—185 A.D.) himself tells us that he was born “in the land of the Assyrians,” meaning Syria rather than the geographical Assyria (Mesopotamia).
He was brought up instructed in Greek philosophy, but, on an extended visit to Rome, first encountered Christianity and became a Christian. He became a disciple of the Christian philosopher Justin Martyr. But after Justin’s death, Tatian became increasingly severe, separating from the Church and joining a Christian offshoot group known as the Encratites (“the self-controlled ones”), who forbade Christians to marry or to eat meat. According to Irenaeus, Tatian “declared that marriage was nothing else than corruption and fornication.” He even, according to the same author, formed his own Gnostic system of doctrine similar to the bizarre system of Valentinus.
Details of Tatian’s life after this are somewhat obscure. After the death of Justin around A.D. 165, it seems he eventually left Rome and returned to the East, where he founded a Christian school of instruction in Mesopotamia, which had a considerable influence over the church in Syria. It was probably here that he composed the Diatessaron, his most famous work.
Although greatly revered in the Syriac Church, Tatian came to be viewed by the Greek theologians of the Church as a heretic on account of his Encratite views.
Nevertheless his Diatessaron, along with his other well-known work the Address to the Greeks, presents an impressive contribution to 2nd-century Christian theology.
What, then, does the Diatessaron show us about Christianity in the second century, and about the New Testament itself? The rest of this article — and of subsequent articles to follow — will concern itself with just this question.
It is a well-known fact that the New Testament Gospels of Matthew, Mark, Luke and John are by no means the only ‘gospels’ ever composed in the ancient world.
Although these four are the earliest examples — or certainly amongst the very earliest — numerous other ‘gospels’ came into circulation during the second and third centuries, possibly even one or two towards the end of the first century.
These other gospels did not portray Jesus of Nazareth in the same way as we find in the New Testament Gospels, but differed from these in their view of Jesus to a greater or lesser extent. For example, the second-century Gospel of Peter, whilst mostly following the narrative we find in Matthew, Mark and Luke, came under suspicion of exhibiting a docetic view of Jesus — that is, the view that he only ‘appeared’ to be human.
Other gospels diverged more wildly. The long known-about but only recently-rediscovered Gospel of Judas claims that none of Jesus’ twelve disciples properly understood Jesus’ identity. The traitor Judas alone understood the mission of Jesus, and betrayed him deliberately in order to fulfil the divine plan.
In the context of this proliferation of ‘gospel’ material in the second century claiming to have been written by various apostles, it was important for Christian theologians of the time to establish what were, and were not, the Gospels held as authentic in the orthodox Church.
Irenaeus, Against Heresies, Book III, ch. XI, §8.
What the Diatessaron shows us is that the idea of a ‘canon’ of four authentic Gospels — Matthew, Mark, Luke and John — was already a well-established idea by the mid-second century.
It was, therefore, not something that Irenaeus or other theologians imposed on Christianity; rather, Irenaeus was making the case for what was already the commonly-held belief of the orthodox Church.
This is a very simple, but a very important observation in an age in which it is fashionable to knock the legitimacy of the New Testament Gospels, and to put other, later and far less authentic ‘gospels’ on a par with those which — as Tatian’s project makes clear — have always been believed by the Church to be the authentic word of God.
In the next part of our series we will look at other general lessons Tatian teaches us about how the Gospels were received in the second century, and how the Church of the time understood them.
 ANF Vol. X. The Diatessaron of Tatian, Introduction, §16.
 ANF Vol. X. The Diatessaron of Tatian, Introduction, §5.
 ANF Vol. X. The Diatessaron of Tatian, Introduction, §17.
 Ibid., §17. See also Irenæus, Against Heresies, Book I, ch. XXVIII, §1, already mentioned.
 See, e.g., http://www.internationalstandardbible.com/A/apocryphal-gospels.html, and, for an example of an early non-canonical gospel, the Gospel According to the Hebrews there described.
 Taken from the Ante-Nicene Fathers (ANF), Vol. X (online Vol. IX), which can be found online at http://www.ccel.org/ccel/schaff/anf09.i.html. With this and subsequent quotations from the Ante-Nicene Fathers, I have slightly adapted the text into more modern English.

References: §8
 §16
 §5
 §17
 §17
 §1