Leitmotifs in Der Rosenkavalier

Something common to many operas composed after the death of Richard Wagner is the use of the leitmotif, a musical idea, tune or melodic "germ" used by a composer to unify a complicated score.   Richard Strauss was one of the earliest inheritors of the leitmotif system and he uses it with abandon in Der Rosenkavalier.  Let's explore some of the leitmotifs used in that opera.