FTP, name this German composer of Elektra and Der Rosenkavalier.
His second opera was based on Ernst von Wolzogen's The Quenched Fires of Oudenarde, and ends with Diemut accepting the love of the magician Kunrad.  His first opera depicts a member of the Holy Society of Peace who saves Freiheld, the wife of the evil Duke Robert, from killing herself.  In addition to Feuersnot and Guntram, he wrote about the surrender at Breda in Friedenstag and about the love of Apollo for a daughter of Peneios in Daphne.  A composer named Flamand and the Countess Madeleine appear in his final opera, the one-act work Capriccio.  He wrote about the sister of Chrysothemis in a 1909 opera based on a play by Sophocles, while Zerbinetta and Bacchus appear in his Ariadne on Naxos.  FTP, name this German composer of Elektra and Der Rosenkavalier.
His second opera was based on Ernst von Wolzogen's The Quenched Fires of Oudenarde, and ends with Diemut accepting the love of the magician Kunrad.  
Richard Strauss