The Renaissance's most influential composer, 500 years later Centuries after his death, Josquin des Prezs achievements as a musical magician-mathematician remain stunning. Marina Muun/The New York Times. by Zachary Woolfe (NYT NEWS SERVICE) .- For the 250th anniversary of Beethovens birth, the classical music field pulled out all the stops last year, even in the midst of pandemic performance cancellations around the world. But while 2021 brings its own significant anniversary in August it will be 500 years since the death of Josquin des Prez, the most influential composer of his age few listeners will know it. At the center of his body of work are 18 grand, unaccompanied choral masses exactly the kind of music that will be largely forbidden for some time yet, for fear of aerosol transmission of the virus. Those masses are the major legacy of the man Peter Phillips, founder and director of the renowned vocal ensemble The Tallis Scholars, called a magician-mathematician in a recent interview.