Nestorius was a Christian theologian and the Patriarch of Constantinople from 428 to 431 AD. He is best known for his controversial views on the nature of Christ, particularly his belief that Christ had two separate natures: one divine and one human. This perspective led to significant theological debates within early Christianity. His teachings were condemned at the Council of Ephesus in 431 AD, which declared that Christ was one person with two natures united in a single divine identity. Nestorius's ideas contributed to the development of the Nestorian Church, which spread throughout the Middle East and Asia.