Question: Who is the saint who is in all likelihood the sister of Mary, the Mother of Jesus, and is mentioned by St. John as being one of the three women standing at the foot of Jesus' Cross? She was the Mother of the Apostles James and John and asked Jesus to give her two sons a place of honor in His kingdom.
Bonus question: How are James and John related to Jesus?
Answer: St. Mary Salome
Bonus answer: First cousins
Mark 16:40
There were also women present looking on from a distance. Among them were Mary Magdalene, Mary the mother of James the younger and Joses, and Salome.
Matthew 27:56
Among them were Mary Magdalene, and Mary the mother of James and Joseph, and the Mother of Zebedee's sons.
John 19:25
Near the cross of Jesus there stood his mother, his mother's sister, Mary the wife of Clopas, and Mary Magdalene.
Read more
http://www.catholic.org/saints/saint.php?saint_id=4962#wiki
http://www.forerunner.com/blog/jesus-cousins-were-the-apostles-james-and-john