An incredibly influencial composer born in Burgundian territory. He was not part of the Burgundian school, but was friends with Guillaume Dufay. Many other composers in the canon of Western art music were influenced by Ockeghem as well. He worked for the French chapels.
Ockeghem's Prenez sur mei is a work that makes great use of imitation. Imitative techniques were used before, but Ockeghem and his pupils were the first to use it regularly as a structural tool. The voices enter at perfect fourths above as opposed to the usual fifth or octave. The lyrics themselves lend to a sort of joke "Take from me your example of love." This phrase is repeated between the three voices.
Ockeghem later goes on to develop the canon even further. An example of this is his Missa Prolationum, which he uses mensuration canon, or canon in which the voices move at different speeds.
Josquin Des Prez's Ave Maria/Virgo serena is another piece that is highly imitative. There is a tendency to use this technique in sacred music, maybe to pound the ideas into listener's heads. Both Ockeghem and Des Prez avoid the harsh dissonances found before. Instead, if they are used they are resolved quickly.
Craig Wright and Bryan Simms. "Music in Western Civilization." (Schirmer, Boston, 2010). pp. 139-141
Milsom, John. "Ockeghem, Johannes." The Oxford Companion to Music. Oxford Music Online. Oxford University Press, accessed April 27, 2014, http://www.oxfordmusiconline.com/subscriber/article/opr/t114/e4804.
Compared work Wiki: Josquin: Ave Maria... Virgo serena