Pope Flavian was the head of the Roman Catholic Church from 446 to 449 AD. He is best known for his role in the early Christian Church during a time of theological disputes, particularly regarding the nature of Christ. Flavian convened the Robber Council of Ephesus in 449, which was later deemed illegitimate due to its controversial decisions. Flavian's papacy was marked by his efforts to uphold the teachings of the Council of Chalcedon, which affirmed the dual nature of Christ as both divine and human. He faced opposition from various factions, including the followers of Eutyches, leading to significant conflicts within the Church.