The 12 stars find their source in the vision of John in our first reading today, which is from the book of Revelation:

‘A great sign appeared in the sky: a woman clothed with the sun, with the moon under her feet, and on her head a crown of twelve stars. She was pregnant and was crying out in birth pangs, in the agony of giving birth.’

Twelve is a number of perfection; it symbolizes the twelve tribes of the Old Testament people and the twelve apostles in the New Testament. In this particular devotion, the number twelve–the twelve stars–are seen in reference to the graces, privileges and charisms received by Our Lady from God. Mary, the Queen of Heaven–a typical baroque title!–is crowned with her perfections, one star for each one of the perfections. Here are these twelve perfections which became the object of the Twelve-Star Devotion:

  1. Predestination before creation
  2. Without original sin conceived
  3. Overshadowed by the Holy Spirit
  4. Virgin before and after giving birth
  5. Birth giver of Jesus Christ
  6. Fullness of grace
  7. Introduced to the Mystery of the Trinity
  8. Seat of Wisdom
  9. Superior to the angels and humans
  10. Installed as Queen
  11. Called to be Mediatrix
  12. Revered by all creatures.

These perfections of Our Lady were recited or sung in litany form or became the object of readings, meditations and musical accompaniment. The devotion was used in parishes but led to elaborate celebrations in monasteries.
Reference to the stars surrounding the head of the apocalyptic woman and their symbolic interpretation did not originate only in the seventeenth and eighteenth centuries. We know of at least one earlier noteworthy example of such practice. Saint Bonaventure, in his Sermons on the Blessed Virgin Mary deals extensively with the twelve-star symbolism. In Sermo VI (devoted to the Assumption of the Blessed Virgin Mary), he compares the twelve stars to Mary’s prerogatives or privileges.