This chapter discusses theological speculation and theological literacy in late antique and medieval Middle East. In the period beginning with the controversy between Cyril and Nestorius in 428 and ending with the Third Council of Constantinople in 680–681, the Christian community of the Middle East splintered into separate and competing churches as a result of disagreements over theological speculation. There was chronic and irresolvable controversy as to how many natures, persons, energies, and wills there were in the Incarnate Christ. The variety of distinct and competing churches that developed include the Chalcedonians, the Miaphysites, and the Church of the East. The question of literacy complicates things further. An estimate of literacy among Christians in the first several centuries AD suggested that no more than 10 percent were able to “read, criticize, and interpret” Christian literature in this time.