Nestorianism is a Christian theological doctrine that emerged in the 5th century, primarily associated with the teachings of Nestorius, the Patriarch of Constantinople. It emphasizes the distinction between the divine and human natures of Jesus Christ, arguing that they are separate entities rather than a single unified nature. This view led to significant theological debates within early Christianity. The doctrine was deemed heretical by the Council of Ephesus in 431 AD, which affirmed the belief in the hypostatic union, the idea that Christ is one person with two natures. Despite its rejection by mainstream Christianity, Nestorianism influenced various Christian communities, particularly in the East, leading to the establishment of the Nestorian Church.