Blessed Constantine XII, last of the Byzantine emperors, martyred by the Turks (1453)

Commemorated on May 29

On this date in 1453, Constantinople, the capital city of the Christian world, was sacked by the forces of Sultan Mehmet (Mohammed) II, bringing it under Turkish rule, where it remains to this day.
  Constantine XII, the last Byzantine Emperor, died defending the city. Sources are sharply divided as to whether he is to be counted as a Christian Martyr. The designation "Blessed Constantine", above, is from the St Herman Calendar, whose compilers cite Russian martyrologies which list him as a saint. However, the Prologue cites the fall of Constantinople while pointedly omitting any praise of Constantine. He accepted (and never publicly renounced) the false "union" of Florence, and so is counted by some as a heretic. Many Orthodox Christians, including many of the people of Constantinople, saw the city's fall as divine retribution for the Empire's acceptance of the union.
  Before his death the Emperor donned soldier's armor and helped to man the ramparts of the City; his body was never found. Though various legends abound, the most likely explanation is that he died with many other defenders and was cast with them into a common grave.