Austrian Classical Period composer Anton Franz Josef Eberl (1755-1807) was extremely gifted and showed his musical talent at a young age. While not so precocious as Mozart, the elder (by nine years) composer befriended Eberl and became his teacher. Quite possibly, some pieces attributed to Mozart were actually written by his student. He spent much of his short adult life in St. Petersburg, Russia. There is no reason to suspect that he slowed his rapid pace of composition, but whatever he wrote there has never been recovered.
More information