MUNICH, Germany —  A German court on Thursday began considering a lawsuit seeking royalties from the heirs of German composer Richard Strauss for nine works, including opera favorites "Der Rosenkavalier" and "Elektra."

In the suit, five heirs of Austrian writer Hugo von Hofmannsthal claim they have a right to about a quarter of the royalties from the operas, for which Strauss wrote the music and his partner von Hofmannsthal the libretto, or words. The payments would amount to nearly $1 million per year.

"Der Rosenkavalier" and "Elektra" remain staples of the repertoire and are still frequently performed by the world's great opera companies.

The von Hofmannsthal heirs cite a series of contracts in which the writer gave Strauss the full rights to his librettos in exchange for a cut of the royalties. Even after the Austrian's death in 1929, Strauss made further contracts with his heirs to secure the rights.

However, none of the contracts clarify how long von Hofmannsthal's heirs are to continue to receive their share of the Strauss royalties. The Strauss heirs contend the royalties should now only be for the operas' music.

The court has asked to see two more of the original contracts between the artists before it can issue a ruling on the case, which is expected sometime in 2007.

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The other works involved in the case are the operas "Die aegyptische Helena," "Ariadne auf Naxos," Die Frau ohne Schatten," "Arabella," "Die Liebe der Danae," and "The Ruins of Athens," as well as the ballet, "The Legend of Joseph."

One of the most important composers of the 19th and 20th centuries, Strauss was considered ahead of his time early in his life, but his association with the Nazis clouded his later years.

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