Mary, called the Magdalene (after Magdala on the west shore of Galilee or possibly from a Talmudic phrase implying adultery), occupies a unique place of honor in the Gospels. In all four Gospels she is named as standing at the foot of Jesus' cross and as one of the women who went to Jesus' tomb to anoint his body, and in three of these she is identified as the first of Jesus' followers to encounter the risen Christ.
Popular imagination has identified Mary Magdalene as a prostitute, in spite of the lack of explicit evidence for this in the Gospels themselves. There are perhaps many reasons for this, but it may have originated in the Gospel of Luke, where Mary is introduced as a woman from whom Jesus cast out seven demons, shortly after a story in which Jesus forgives the sins of "a woman in the city who was a sinner" and blesses her. There is no apparent connection between the two people in Luke except proximity.
Now, here's where things get complex. (It might help to fetch Granny's weathered copy of the Good Book at this point and follow along.) In John 11 Mary of Bethany, sister of Martha and Lazarus, is identified as "that Mary who anointed the Lord with fragrant oil and wiped His feet with her hair," certainly the actions of the sinner in Luke 7. Mary of Bethany performs those very actions in the next chapter of John, when Jesus dines at her and Martha's house. Some have therefore argued that this later act is what John is referring to and Bethany and the "sinful woman" are not the same. Others say that John, writing many years after Mary's death, wants to make sure that his readers understand clearly that this Mary is the same sinner who anointed Jesus on an earlier occasion and was now doing so again. Luke, they say, may have wished to obscure this fact when he wrote his gospel out of respect for the still-living Mary.
The link connecting Mary of Bethany and the "sinful woman" to Mary Magdalene is more of an intuitive leap. Magdalene occupies such a central role during the Passion and the Resurrection while Mary of Bethany, who plays such an important part in Jesus' ministry, is not mentioned at all. Since Mary of Bethany is so particularly blessed, it is argued, it seems strange that she should so abruptly and unaccountably disappear from the narrative and an entirely different Mary step in. The two must be identical, they feel.
Though some may feel that saying this holy and virtuous woman was a prostitute earlier in life is character assassination, in the context of Christian belief it has the opposite effect. Christ, it is believed, came especially for the ungodly, the broken-hearted and hopeless. For someone whose life was mired in sin to recognize Jesus of Nazareth as the Son of God and fall at his feet in love to do him honor, while the self-righteous religious leaders who have invited him to dinner look on in horror, provides a powerful testimony to God's power to heal the broken in spirit, and Magdalene becomes an icon to those who feel lost and unworthy. That such a person should be chosen to be the first to behold the risen Christ's glory affirms Jesus' teaching that in the Kingdom of God, the last shall be first.
In general, Protestant and Eastern churches have traditionally believed these three to be separate, while the Latin tradition holds that Madgalene, Bethany, and the sinful woman are the same. The traditions of the Greek Church say that Mary retired to Ephesus, (which is supported by Gregory of Tours) and that her relics were preserved at Constantinople. The French believe that Mary and Lazarus came with some others to Provence and that the head of St. Mary Magdalene rests in the church of La Sainte-Baume.