Adrian Willaert
Sometime around 1515 Willaert first went to Rome.  There is a story, which is probably true, that Willaert was surprised to find the Pope’s choir singing something he had composed.  The choir thought it had been composed by Josquin, who was very famous by then.  When the young Willaert told them that he himself was the composer, the choir did not believe the young man, and refused to sing it again.