He conducted the premieres of two PERSON@1 operas , Tristan und Isolde and Die PERSON@2 , in NUMBER@1 and NUMBER@2 respectively ; both were immensely successful .

He conducted the first performances of two PERSON@1 operas : Tristan und Isolde -LRB- NUMBER@1 -RRB- and PERSON@3 -LRB- NUMBER@2 -RRB- .
