Theodore of Mopsuestia was a major Christian theologian and bishop who lived from around 350 to 428 CE. Born in Antioch, he studied under prominent teachers and became the leading systematic thinker of the Antiochene school of biblical interpretation. This school emphasized historical and literal readings of Scripture. He served as the Bishop of Mopsuestia in southern Anatolia for most of his adult life, where he was initially widely respected.

He was an exceptionally prolific writer, though most of his original Greek works have been lost. His surviving writings, preserved mainly in Syriac translations and fragments, include extensive commentaries on books of the Bible, catechetical lectures, and theological treatises.

Theodore's historical importance is profound and complex. Modern scholars recognize him as a foundational figure who developed a sophisticated method of interpretation, distinguishing historical events in the Old Testament from their symbolic fulfillment in Christ. His theological writings on the nature of Christ aimed to protect both the full divinity and full humanity of Jesus. However, after his death, his ideas were condemned as a source for the heresy known as Nestorianism. He was officially denounced as a heretic by an ecumenical council in 553 CE, which led to the destruction of his works in the Greek-speaking world. Despite this condemnation in the West, his writings were preserved and became highly influential within the Syriac Christian tradition, where he is honored as "the Interpreter."