Tatian was a 2nd-century Christian theologian and writer born in Assyria. After traveling to Rome, he became a student of Justin Martyr and established a Christian school there. He is most famous for composing the Diatessaron, a literary harmony that synthesized the four Gospels into a single continuous narrative. While his ascetic views and connections to Gnostic thought led to his expulsion from the church, his written works remained highly influential in Syriac-speaking regions for several centuries.