Saint Mary Magdalene was a woman who travelled with Jesus and was a witness to the Crucifixion and Resurrection of Jesus.
Saint Mary Magdalene is first mentioned in the Gospels, where in Luke records some of her story in Luke 8:1-3 -
Soon afterwards he went on through cities and villages, proclaiming and bringing the good news of the kingdom of God. The twelve were with him, as well as some women who had been cured of evil spirits and infirmities: Mary, called Magdalene, from whom seven demons had gone out, and Joanna, the wife of Herod's steward Chuza, and Susanna, and many others, who provided for them out of their resources.
In the Gospels of Luke, Mark, Matthew and John, Saint Mary Magdalene is present with the Virgin Mary, Mary, wife of Clopas, and May mother of James and Joseph at the crucifixion. Saint Mark records that she was present alongside the Virgin Mary at the burial of Jesus Christ. All four gospels list that Saint Mary Magdalene was the first person to discover the empty tomb.
Saint Mark writes that Saint Mary Magdalene, Mary the Mother of James and Salome went to the tomb to find it empty and a young man dressed in white inside telling them that Jesus had risen. Saint Matthew writes that Saint Mary Magdalene and the "Other Mary" went to the tomb and a massive earthquake struck. As they stood in the midst of it, an angel dressed in white rolled the stone away and Jesus came to them, telling them to tell the disciples he would meet them in Galilee. Saint Luke's version closely follows Saint Mark's except that there were two men dressed in white inside the tomb who told them Jesus had risen.
In the Gospel of John, Saint Mary Magdalene went to the tomb alone early in the morning to find the tomb empty. She immediately ran to tell Saint Peter and the "Beloved Disciple" who returned with her to find the tomb empty. When the two men returned home, she sat alone outside and saw two angels sitting where the body had been. The risen Christ then approached her and told her to go and tell the others that he had Risen. Because of her being sent to the apostles to tell them of the good news, she is often referred to as the Apostle to the Apostles.
The notion of Saint Mary Magdalene being a former prostitute or loose woman only came about during the Papacy of Pope Gregory I when he gave an influential and popular homily in 591 AD. :
She whom Luke calls the sinful woman, whom John calls Mary, we believe to be the Mary from whom seven devils were ejected according to Mark. What did these seven devils signify, if not all the vices? It is clear, that the woman previously used the unguent to perfume her flesh in forbidden acts. What she therefore displayed more scandalously, she was now offering to God in a more praiseworthy manner. She had coveted with earthly eyes, but now through penitence these are consumed with tears. She displayed her hair to set off her face, but now her hair dries her tears. She had spoken proud things with her mouth, but in kissing the Lord's feet, she now planted her mouth on the Redeemer's feet. For every delight, therefore, she had had in herself, she now immolated herself. She turned the mass of her crimes to virtues, in order to serve God entirely in penance.
— Pope Gregory I (homily XXXIII)
It is important to note, however, that few early Church fathers made the same association. Saint Ambrose and Saint John Chrysostom wrote that Saint Mary Magdalene was likely a virgin. The Eastern Orthodox churches saw Saint Mary Magdalene only as a disciple and held to the tradition that she lived as a companion to the Virgin Mary after the resurrection. Saint Gregory of Tours wrote in the late 500s that he believed Saint Mary Magdalene retired in Ephesus with the Virgin Mary where they lived the rest of their lives and that Saint Mary Magdalene was buried there in the city. Modestus, Patriarch of Jerusalem, believed that she came to Ephesus to live with Saint John following the death of the Virgin Mary. Saint Pope John Paul II wrote in his apostolic letter Mulieris Dignitatem (On the dignity and vocation of women) :
The women are the first at the tomb. They are the first to find it empty. They are the first to hear 'He is not here. He has risen, as he said.'[Mt 28:6] They are the first to embrace his feet.[cf. Mt 28:9] The women are also the first to be called to announce this truth to the Apostles.[Mt 28:1–10] [Lk 24:–11] The Gospel of John (cf. also Mk 16:9 emphasizes the special role of Mary Magdalene. She is the first to meet the Risen Christ. [...] Hence she came to be called "the apostle of the Apostles". Mary Magdalene was the first eyewitness of the Risen Christ, and for this reason she was also the first to bear witness to him before the Apostles. This event, in a sense, crowns all that has been said previously about Christ entrusting divine truths to women as well as men.
— John Paul II
The liturgical commemoration of Saint Mary Magdalene was elevated from an obligatory memorial to Feast Day on July 10th, 2016. Many of her relics are held in Catholic Churches throughout France, with her skull and the noli me tangere on display at Saint--Maximin-la-Sainte-Baume. At Mount Athos, specifically the Simonopetra Monastery, the monks have kept her left hand relic preserved.