Mary Magdalene's story is intimately linked with Jesus. She plays a starring role in one of the most powerful and important scenes in the Gospels.
When Jesus is crucified by the Romans, Mary Magdalene was there supporting him in his final terrifying moments and mourning his death. She also discovers the empty tomb, and she's a witness to the resurrection. She was there at the beginning of a movement that was going to transform the West.
The window shows Mary holding the jar of ointment with which she annointe Jesus, and carrying a a wreath of roses, a symbol of chastity regained. These relate to the story of Mary in the gospels
36 When one of the Pharisees invited Jesus to have dinner with him, he went to the Pharisee’s house and reclined at the table. 37 A woman in that town who lived a sinful life learned that Jesus was eating at the Pharisee’s house, so she came there with an alabaster jar of perfume. 38 As she stood behind him at his feet weeping, she began to wet his feet with her tears. Then she wiped them with her hair, kissed them and poured perfume on them.
39 When the Pharisee who had invited him saw this, he said to himself, “If this man were a prophet, he would know who is touching him and what kind of woman she is—that she is a sinner.”
40 Jesus answered him, “Simon, I have something to tell you.”
“Tell me, teacher,” he said.
41 “Two people owed money to a certain moneylender. One owed him five hundred denarii,[a] and the other fifty. 42 Neither of them had the money to pay him back, so he forgave the debts of both. Now which of them will love him more?”
43 Simon replied, “I suppose the one who had the bigger debt forgiven.”
“You have judged correctly,” Jesus said.
44 Then he turned toward the woman and said to Simon, “Do you see this woman? I came into your house. You did not give me any water for my feet, but she wet my feet with her tears and wiped them with her hair. 45 You did not give me a kiss, but this woman, from the time I entered, has not stopped kissing my feet. 46 You did not put oil on my head, but she has poured perfume on my feet. 47 Therefore, I tell you, her many sins have been forgiven—as her great love has shown. But whoever has been forgiven little loves little.”
48 Then Jesus said to her, “Your sins are forgiven.”
49 The other guests began to say among themselves, “Who is this who even forgives sins?”
50 Jesus said to the woman, “Your faith has saved you; go in peace.”
See also Mattheew 26:7, Mark 14:3 and John 12:3. For more information from the BBC website about Mary Magdelene.