This masterful initial M, colorful and crowded with playful animals and fantastic forms, recalls the announcement to the Virgin Mary by the Angel Gabriel that she will conceive and bear a son. The text introduced here is the Response for the First Sunday in Advent: Missus est Gabriel Angelus ad Miriam Virginem... (The Angel Gabriel was sent to Mary...). The decorated initial is related in style to a set of choir books made by Belbello for the Church of Sts. Giovanni e Paolo in Venice. Belbello's style has been associated with another artist, the Master of the Murano Gradual (shown nearby), with whom he possibly collaborated in Venice.
Belbello's career placed him in Milan, Mantua, Pavia, and Venice. His services were highly sought by Renaissance princes, and his style was influential and widespread in northern Italy.