Pope Sixtus III served as the head of the Roman Catholic Church from 432 to 440 AD. He is known for his efforts to promote the Christian faith during a time when the Church was facing various challenges, including theological disputes and the rise of heresies. Sixtus III is also recognized for his contributions to the development of church architecture, particularly the construction of the Basilica di Santa Maria Maggiore in Rome. During his papacy, Sixtus III worked to strengthen the Church's authority and unity. He supported the decisions made at the Council of Ephesus in 431 AD, which affirmed the title of Theotokos for the Virgin Mary. His leadership helped to solidify the Church's position in a rapidly changing world, ensuring the continuation of Christian teachings and practices.