The Baroque period is generally considered to begin with the 17th century, in 1600. Reference: Donald Grout, "A History of Western Music", ch. ix.
Also, if you listen to this music it has all the hallmarks of Late Renaissance - the spare vocal lines, the polyphonic structure, the principle of imitation. . . Alexander Agricola and Adam von Fulda are considered Renaissance composers.
One important thing to note is that the Baroque in music starts much later than the Baroque in art and architecture, so the dates are different.
- for what it's worth, I'm the music columnist for my church bulletin, have read Grout cover-to-cover, and have a real expert in our choirmaster whom I consult with any picky questions (he has a D.M.A. from Juilliard so he officially knows everything.) ;-)
Thank you! I’ll defer to your expertise. Merry Christmas!