This holy defender of the One, Holy, Catholic and Apostolic Church labored in the final days of the Byzantine Empire, when, pressed on all sides by the Turks, the Emperor in desperation sought union with (or rather submission to) the Papacy in hopes of obtaining aid from the West. It was St Mark who stood almost alone to prevent such a disaster to the Faith.
  He was born in Constantinople in 1392 to devout parents. He received a thorough education and seemed destined for a secular career, but at the age of twenty- six he abandoned all worldly claims and became a monk in a small monastery in Nicomedia. Soon the Turkish threat forced him to return to Constantinople, where, continuing in the monastic life, he wrote a number of treatises on prayer and the dogmas of the Church. In time he was ordained priest, then, at the insistence of the Emperor John VIII Paleologos was made Metropolitan of Ephesus. The Emperor also prevailed on him to join the delegation which traveled to the Council of