Vatican II was overseen by Mary

When he was still archbishop of Venice, Italy, Pope Saint John XXIII (1881-1963) had promised to recite daily the complete fifteen mysteries Rosary... His spirituality was marked by the intense love of the Eucharist and a filial veneration of the Blessed Virgin. His motto was "To Jesus through Mary."

After summoning the Second Vatican Council, the pope went to Loreto and Assisi to ask for the intercession of Mary and Saint Francis on behalf of the Council. He then scheduled the session between the feasts of the Motherhood of Mary and of the Immaculate Conception.

Pope from 1958 to 1963, Saint John XXIII published no less than 501 documents wholly or partly dedicated to Mary. In his broadcast message of March 27, 1960, he stated: "Devotion to the most holy Virgin Mary only tends to make our faith more robust, more prompt and more effective; to make our charity more ardent, and our Christian commitment more alive and more fruitful."

Source: Dictionnaire encyclopédique de Marie - Authors: P.-R. Ambrogi and D. Le Tourneau, DDB