In his journey to the Empyrean, Dante had visited the seven lower celestial spheres: the spheres of the moon, Mercury, Venus, the sun, Mars, Jupiter, and Saturn. Then in Canto XXII he ascended to the sphere of the fixed stars. Beatrice was his guide.
The constellation to which Dante and Beatrice ascended was Gemini. This was because the sun was in the constellation Gemini when Dante was born. From this vantage point, Dante looked downward and saw the earth and all the celestial spheres that he had already visited.
Then in Canto XXIII, Dante saw a host of brilliant lights. They were the spirits of those whom Christ had won for Himself through His triumph over the forces of evil.
Dante also saw Christ himself. It was His splendor that imparted light to the souls that He had redeemed. Dante’s vision was overpowered by the brilliance of Christ. Since Dante’s eyes were not yet strong enough to look upon Him, Christ ascended to the Empyrean.
Nevertheless, Dante’s eyes were stronger than they were before. When Dante and Beatrice were in the sphere of Saturn, Beatrice did not dare to smile. Her smile would have reduced Dante to dust and ashes. Now, however, Dante was able to enjoy the smile of Beatrice without suffering any harm.
Dante then saw Mary, the rose in which the divine Word became flesh. Then a being that called himself angelic love descended from the Empyrean and became a brilliant crown that revolved around her.
As Mary ascended to the Empyrean, following her Son, the other spirits remained in the presence of Dante and sang Regina Coeli as Mary ascended.
The Latin title of this song means “queen of heaven.” It reflects the Mariolatry (the adoration of Mary) that was prevalent in the Middle Ages and is still practiced in the Roman Catholic Church.
The term “Mariolatry” is somewhat inaccurate, though the dictionary sanctions its use. If I understand the Roman Catholic system correctly, the term latria is a form of worship reserved for God alone. The adoration of the saints is a lesser form of worship called dulia, while the adoration of Mary is hyperdulia, which is intermediate between dulia and latria.
In contrast, Lutherans like myself honor Mary as the mother of God, but do not offer her any form of adoration or worship. I am not certain whether or not all Protestants apply the term “mother of God” to Mary. Nestorius, a patriarch of Constantinople, objected to this title, but it was declared legitimate by the Council of of Ephesus in 431 A.D.
As Canto XXIII draws to a close, Dante enthusiastically speaks of the riches that believers will enjoy in heaven and briefly mentions St. Peter, who will appear in the next canto.
Reference:
“Paradiso” of “The Divine Comedy” by Dante Alighieri; Italian text with English translation by Allen Mandelbaum; Notes by Anthony Oldcorn, Daniel Feldman, and Giuseppe di Scipio