Feast of the Assumption of Mary: A major national holiday in France

In 1636, the Blessed Virgin asked Mother Anne Marie of Jesus Crucified, a stigmatized French nun, that France be consecrated to her. The following year, the King of France, Louis XIII, "in the secret of his heart," consecrated his person and his Kingdom to Mary, and he and the Queen, Anne of Austria, multiplied prayers and pilgrimages to obtain an heir who had been awaited for 22 years.

The Mother of God responded by appearing to a friar called Brother Fiacre at Our Lady of Victories parish in Paris. She asked for three novenas of petition: one to Our Lady of Cotignac in Provence, one to Our Lady (Notre Dame) of Paris, and one to Our Lady of Victories. The apparition was quickly recognized as authentic, and the Queen was notified of the Virgin Mary’s request. Brother Fiacre completed the three novenas on December 5th and a royal heir, Louis XIV, was born nine months later to the day, receiving the baptismal name of Louis "Dieudonné" ("God-given").

As soon as the Queen was certain of her pregnancy, without waiting for the birth to know whether the child would be a boy or a girl, King Louis XIII published the official Edict on February 10, 1638, by which he solemnly consecrated France to the Virgin Mary. He also instituted an annual public procession to take place every August 15th, the feast of the Assumption of Mary, in all the churches of all the dioceses of the Kingdom.

To this day, August 15th is still a national holiday in France.

Encyclopedia Maria Volume IV - Beauchesne 1956.