What is saint cyrille?

Saint Cyrille is also known as Cyril of Alexandria. He was a prominent theologian and bishop of Alexandria in Egypt during the fifth century. He was known for his defense of orthodox Christian doctrine, especially against the teachings of Nestorius, who denied the mother of Jesus, Mary, the title of "Theotokos," or "God-bearer."

Saint Cyrille is also notable for his contributions to the development of Christian doctrine, particularly with regard to the nature of Christ and the Trinity. He was instrumental in formulating the doctrine of the hypostatic union, which maintains that Jesus Christ is fully God and fully man.

Saint Cyrille is venerated as a saint in both the Eastern and Western Christian traditions. His feast day is celebrated on June 27th in the Eastern Orthodox Church, and on February 9th in the Roman Catholic Church.