Name days on March 21
Saints and feasts of March 21

Thomas the Apostle
Apostle, Θωμάς
St. Thomas, called the Twin, was one of the Twelve Apostles of the Lord. It was he who said he would not believe unless he touched the wounds of the risen Christ, and who, beholding the Lord eight days after Pascha, made the great confession, my Lord and my God. His honest doubt became for all generations a confirmation of the Resurrection.
James of Catania
Hierarch, Ιάκωβος ο Ομολογητής
St. James was a monk of the Studion monastery who became Bishop of Catania in Sicily in the ninth century. For his defense of the holy icons during the second iconoclast persecution he was subjected to hunger, imprisonment and exile.
Thomas of Constantinople
Hierarch, Θωμάς Πατριάρχης
St. Thomas was Patriarch of Constantinople at the beginning of the seventh century, in the reign of the emperor Phokas. Tradition relates that he was a man of great virtue who, troubled by a sign foretelling calamities for the Church, asked St. Theodore of Sykeon to pray that he might die before seeing them, and reposed soon after.
Serapion of Sidon
Hierarch, Σεραπίων
St. Serapion was a friend of St. Anthony the Great and St. Athanasius, and became Bishop of Thmuis in the Nile delta in the fourth century. A learned man, he defended the Orthodox faith against the Arians and wrote a treatise on the divinity of the Holy Spirit; an ancient liturgical prayer book bears his name.
Philemon and Domninos
Martyr, Φιλήμων και Δομνίνος
Sts. Philemon and Domninos were Christians of Rome who, according to tradition, traveled through Italy preaching the Gospel. They were arrested, tortured and beheaded for their confession of Christ.
Seraphim of Vyritsa
Venerable, Σεραφείμ της Βίριτσα
St. Seraphim of Vyritsa was born in 1866 and was a successful merchant in St. Petersburg before he and his wife entered monastic life. He became the spiritual father of the Alexander Nevsky Lavra and, after its closure, lived at Vyritsa near St. Petersburg, where he received countless visitors and prayed for Russia through the years of persecution and war.