Immediately following the Feast of the Exaltation of the Holy Cross, the Church commemorates the Blessed Virgin Mary as Our Lady of Sorrows. This primarily remembers Mary standing at the foot of the cross, keeping a sorrowful vigil as she saw her son dying. Over time it actually developed to include what are called the Seven Sorrows of the Blessed Virgin Mary, growing out of the prophecy of St. Simeon, who, at the time of the Presentation, told Mary that a sword should pierce through her own soul. 

These seven sorrows are: 
The Prophecy of Simeon concerning the Jesus, born for the rise and fall of many.
The Flight into Egypt of the Holy Family.
The Loss of the Child Jesus for Three Days.
The Meeting of Jesus and Mary on the way to Calvary.
The Crucifixion, where Mary stands at the foot of the cross.
The Descent from the Cross, with Jesus placed in Mary's arms.
The Burial of Jesus. 

The title of Our Lady of Sorrows is very closely related to our own title of Our Lady of the Atonement – we see our primary image of the Blessed Mother holding her Son who holds the cross (St. Simeon’s prophecy), and we have the image of Our Lady of the Atonement as the Pieta, as she holds the lifeless body of her Son when he was taken down from the cross. 

This commemoration helps us to remember Mary’s sacrifice for our salvation, and also the importance of avoiding things in our own lives which would cause further sorrow to Mary, who is our Mother. 

O God, who didst will that in the passion of thy Son a sword of grief should pierce the soul of the blessed Virgin Mary his Mother: Mercifully grant that thy Church, having shared with her in his passion, may be made worthy to share in the joys of his resurrection; through the same thy Son Jesus Christ our Lord, who liveth and reigneth with thee and the Holy Spirit, one God, for ever and ever. Amen.