La Favorite by Gaetano Donizetti (1797-1848) is an opera based on a French drama with origin to a Spanish work: a young man's adventures with a beatiful lady who turns out to be the favourite of the king. Here is the theme from act IV for piano solo. Easy to early intermediate, 2 pages, 34 bars, 2:30 min. 
With downloadable mp3 for audio help.