Ddufay (and many other important composers of his day) born in "Northern France near Belgium", and he spend his career in "Italy".
Italy in the fifteenth century was a wild place to be. There was no bound together nation as we consider it today. Rather there were various fiefdoms and families competing for power and matchless quality. Their music was wild, as well, brimming with reckless interests. That is until multi day, when an even tempered arranger touched base from the north. His music was refined, controlled, and superbly executed. His name was Guillaume Dufay, and he took the best of the Italian music and made something new.