__Feast of St Cyril of Alexandria Bishop and Doctor.
Because we are far removed from the time of culture, we find it difficult to concieve the arguments and battles fought over certain doctrines in the Church. One of these was the concept of "Theotokos" literally God-bearer as applied to Mary. This argument raged in the 300s and 400s and was evetnually settled at the Council of Ephesus in 439AD.
_Cyril was the leader of the Theotokos group and argued that since Jesus became man with a rational soul he must have had a mother. The church does not say that Mary is the mother of the divine; that would be impossible for a human to give birth to the divine, but Jesus is God so Mary is the mother of God.
While we think of these things now as commonplace, in their times they were causes of great dispute. Men like Cyril were clear thinkers and great theologians who, with the help of the Holy Spirit, were able to keep the church on the right track and away from heresy. Thank God for them.