19 is based on the Csárdás nobles by Kornél Ábrányi, better known as a music critic than as a composer.
Halfway through the piece, the mood changes drastically and a memorable four-note melody is introduced, taking the main focus of this section.
In the climax and ending of the piece, we revisit some of Liszt’s flashy writing from his youth.
[1] The pianist Vladimir Horowitz wrote his own piano transcription of the 19th Rhapsody, remarking to Thomas Frost that Liszt was "quite old" when he composed it.
This rhapsody may not be as showy as its predecessors, but in my humble estimation it is more daring, more advanced harmonically and ... difficult enough.