Recent developments in the biography of Josquin des Prez have focused new attention on the motet Ave Maria …… virgo serena. In 1974, Thomas Noblitt showed that watermark evidence assigned a copy of the piece in Munich, Bayerische Staatsbibliothek, Mus. ms. 3154 to 1476; the dating appeared unassailable philologically, and the style of the music tied it to a repertory created at the court of Milan in a period when Josquin supposedly worked there. But with the discovery by Lora Matthews and Paul Merkley that Josquin had no connection with Milan until 1484, a potential conflict between style, date, and perhaps authorship has emerged. Reexamination of the motet and its transmission affirms both the Milanese character of the music and Josquin's authorship; a more intensive investigation of the relationship between script and paper in Munich 3154, however, shows that the Ave Maria represents a previously unrecognized phase in the work of its copyist, datable to 1485 or an adjacent year. Even against this revised background, Munich 3154 remains the earliest securely datable source for any music of Josquin, and the Ave Maria seems in all likelihood the earliest composition of his that we can identify.