Complex sentence: In 1884 Barrett had appeared in "Hamlet", just to promptly return to melodrama, whereas he wouldn't find much success ever in any Shakespearian role, except once when incarnating Mercutio of "Romeo and Juliet".
Split into simpler sentences: In 1884 Barrett had appeared in "Hamlet", just to promptly return to melodrama. He wouldn't find much success ever in any Shakespearian role, except once when incarnating Mercutio in "Romeo and Juliet".