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According to the Gospel of John, Mary of Clopas (Ancient Greek: Μαρία ἡ τοῦ Κλωπᾶ, María hē toû Clōpâ) was one of the women present at the crucifixion of Jesus and bringing supplies for his funeral. The expression Mary of Clopas in the Greek text is ambiguous as to whether Mary was the daughter or wife of Clopas, but exegesis has commonly favoured the reading "wife of Clopas". Hegesippus identified Clopas as a brother of Joseph. In the latest official edition of the Roman Martyrology of the Catholic Church she is commemorated with Salome on April 24.
Along with Mary Magdalene and "Mary" Salome, Mary of Clopas is known as one of the Three Marys at the tomb of Jesus. Her relics are said to be in France at the Church of the Saintes Maries de la Mer.
General info from Wikipedia.org