March 25, 1436
The finished Duomo (dome), designed by Filippo Brunelleschi, of the Basilica of Santa Maria del Fiore (St. Mary of the Flowers) is consecrated. Pope Eugenius, along with seven cardinals, 37 bishops, art patron Cosimo d’Medici, and nine members of the Florentine government, dedicated the Cathedral and its dome to Mary.
In Catholicism, the Feast of the Annunciation–March 25th on the calendar–celebrates the moment that the angel Gabriel revealed to Mary that she would conceive and give birth to Jesus Christ. As such, the date has traditionally been an important deadline for the completion of Church-commissioned artwork, so that the work could be ceremonially dedicated to Mary on this meaningful day.
The Papal choir performed a motet by Guillaume Dufay that was written specifically for the consecration. In the world of music, this artwork is as momentous as the completion of the Duomo; it is considered to this day to be one of the most important pieces of music ever written in honor of a specific occasion.