Original: Popular composers of opera seria included Alessandro Scarlatti , Johann Adolf Hasse , Leonardo Vinci , Nicola Porpora , George Frideric Handel , and in the second half of the 18th century Tommaso Traetta , Gluck , and Mozart .
Simplified: Popular composers of opera seria included Hasse , Vinci , Jommelli , George Frideric Handel , Piccinni , Paisiello , Cimarosa , Gluck , and Mozart .