Grove speculates that it was first published in 1515 and written while Divitis was working for the French royal court (starting in 1510), hence the 1510-1515 date. Based on four voice motet "Quem dicunt homines" by Richafort (http://elvis.music.mcgill.ca/node/1062). Source: Antonius Divitis, Collected Works, ed. B. A. Nugent, Recent Researches in the Music of the Renaissance, 94 (Madison, Wisc.: A-R Editions, 1993), 39-77.