May 11 (Eastern Orthodox liturgics)
May 10 – Eastern Orthodox Church calendar – May 12
All fixed commemorations below celebrated on May 24 by Orthodox Churches on the Old Calendar.
For May 11th, Orthodox Churches on the Old Calendar commemorate the Saints listed on April 28.
Saints Saints Cyril and Methodius, Equals-to-the-Apostles.
St. Clement of Ohrid.
Saint Naum of Preslav.
St. Rostislav the Prince of Great Moravia, Confessor of the Faith.
St. Mamertus, Archbishop of Vienne.
Sancreed church and war memorial, Cornwall.
St. Gangulphus of Burgundy.
St. Odo of Cluny.
St. Odo of Cluny.
St. Majolus of Cluny.
Saint Sophia Cathedral in Kiev.
Greek Sources
Russian sources
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Wikipedia