Template:May 21

Saints Constantine and Helen, Equals to the Apostles and rulers of the Roman Empire; Saint Adelphios, Bishop of Onouphis, in Byzantine Egypt (ca.362 or ca.431); Saint Constantine (in baptism Yaroslav) and his children Saints Michael and Theodore, Wonder-workers of Murom; Saint Cassian the Greek, monk of Uglich; Saint Agapitus, Abbot of Markushev (Vologda); Righteous New-Martyr Pachomius of Patmos (Mount Athos); Saint Basil, Bishop of Ryazan; Saint Hospicius of Trier (Gaul); celebration of the Vladimir icon of the Theotokos; repose of Elder Isaac of Dionisiou Monastery (Mount Athos)