He was one of the greatest philosophers of the Middle Ages, coming at the beginning of the great flowering that came with the rediscovery of the works of Aristotle. He had a great interest in science and astronomy and his learning gave him the title, as a Doctor of the Church, of Doctor Universalis, the “Universal Doctor.”

  In 1260 the Pope made him Bishop of Regensburg, a post that he held for three years before resigning it. He made great efforts to secure peace between people and between cities. He died at Cologne in 1280.

  See the articles in Wikipedia and the Catholic Encyclopaedia.

  ‘Saturdays stand out among those days dedicated to the Virgin Mary. These are designated as memorials of the Blessed Virgin Mary. This memorial derives from Carolingian times (9th century), but the reasons for having chosen Saturday for its observance are unknown. While many explanations of this choice have been advanced, none is completely satisfactory from the point of view of the history of popular piety.

  ‘Whatever its historical origins may be, today the memorial rightly emphasizes certain values to which contemporary spirituality is more sensitive. It is a remembrance of the maternal example and discipleship of the Blessed Virgin Mary who, strengthened by faith and hope, on that “great Saturday” on which Our Lord lay in the tomb, was the only one of the disciples to hold vigil in expectation of the Lord’s resurrection. It is a prelude and introduction to the celebration of Sunday, the weekly memorial of the Resurrection of Christ. It is a sign that the Virgin Mary is continuously present and operative in the life of the Church.’

  Directory on Popular Piety and the Liturgy (2001), §188