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Later 15th - and early 16th - century figures in the genre included Johannes Ockeghem and Josquin des Prez , whose works cease to be constrained by " formes fixes " and begin to feature a pervading imitation ( all voices sharing material and moving at similar speeds ) , similar to that found in contemporary motets and liturgical music .
 Johannes Ockeghem, Josquin des Prez
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 Johannes Ockeghem, Josquin des Prez