Complex sentence: Second, there was a fear amongst the authorities in Germany and Austria that the performance German operas would attract nationalist and revolutionary followers which would have added to the difficulties of a novice composer seeking an opportunity for his new opera to be performed.
Split into simpler sentences: Second, there was a fear among the authorities in Germany and Austria that the performance of operas in German would attract nationalist and revolutionary followers. This would have added to the difficulties faced by a novice composer seeking an opportunity for his new opera to be performed.