Meyerbeer 's personal attachment to Judaism was a mature personal decision – after the death of his maternal grandfather in 1811 he wrote to his mother ' Please accept from me a promise that I will always live in the religion in which he died ' . In his diaries he noted significant family events including birthdays , not by their Gregorian calendar occurrence , but by their Jewish calendar date . Moreover , he regularly suffered from ( and / or imagined ) anti @-@ Jewish slights throughout his life , warning his brothers frequently in his letters against richess ( Yiddish for ' Jew @-@ hatred ' ) . Writing to Heinrich Heine in 1839 , he offered the fatalistic view :