 Mendelssohn disapproved of Meyerbeer 's works on moral grounds , believing Robert le diable to be ' ignoble ' . 
 Mendelssohn disapproved of Meyerbeer <a href='null_genetive' title='1'><mark>'s</mark></a>works on moral grounds , believing Robert le diable to be ' ignoble ' . 
Mendelssohn disapproved of Meyerbeer  works on moral grounds , believing Robert le diable to be ' ignoble ' .