Saint Margaret was born in A.D. 1242, the last daughter (ninth of 10 children) of the King of Hungary, Bela IV, and Maria Lascaris, the daughter of the emperor of Constantinople. Saint Margaret is the niece ofSaint Elizabeth of Hungaryand the younger sister of Saint Kinga and Blessed Yolanda.
Before Margaret's birth, her parents had promised Our Lord to dedicate their child to Him if Hungary was victorious over the invading Tartars. After their prayers were answered, now nearly four, they placed Margaret with the Dominican monastery of Veszprim. At the age of 12 Saint Margaret moved to a new monastery built by her father at Buda, and made profession of her final vows before Humbert of Romans.
Saint Margaret lived a life totally dedicated to Christ crucified and by her example of living inspired her sisters to follow her in her asceticism, works of mercy, pursuit of peace, and striving to be of humble service. Saint Margaret opposed all attempts by her father to arrange a political marriage between herself and King Ottokar II of Bohemia. Saint Margaret had a special love for the Eucharist and the Passion of Christ and showed a special devotion to the Holy Spirit and Our Lady.
Saint Margaret died on 18 January 1270. However, she was venerated as a saint during her lifetime. After her death the canonization investigation was begun immediately, including the testimony of 77 persons who said they had received miracles as a result of Saint Margaret's intercession. However, it was not until 19 November 1943 that Saint Margaret was canonized by Venerable Pope Pius XII, on the feast day of her cousin, Saint Elizabeth of Hungary.
(Edited from acta-sanctorum.blogspot.ca)
O God of truth,
through the Holy Spirit
you blessed our sister Margaret with true humility.
Teach us that same integrity
so that we may constantly turn from our selfishness
to your love.
We ask this through our Lord Jesus Christ, your Son,
who lives and reigns with you and the Holy Spirit,
one God, for ever and ever.