Complex sentence: Jules Émile Frédéric Massenet (12 May 184213 August 1912) was a French composer best known for his thirty-five operas, of which the two most frequently staged are "Manon" (1884) and "Werther" (1892).
Split into simpler sentences: Jules Émile Frédéric Massenet (12 May 184213 August 1912) was a French composer best known for his operas, of which wrote more than thirty. The two most frequently staged are "Manon" (1884) and "Werther" (1892).