During the early 5th century, the School of Edessa had taught a Christological perspective stating that Christ's divine and human nature were distinct persons. A particular consequence of this perspective was that Mary could not be properly called the mother of God but could only be considered the mother of Christ. The most widely known proponent of this viewpoint was the Patriarch of Constantinople Nestorius. Since referring to Mary as the mother of God had become popular in many parts of the Church this became a divisive issue.