50, is a cantata for tenor solo, four-part male chorus and orchestra by German composer Johannes Brahms.

He chose as his text the dramatic poem of the same name by Johann Wolfgang von Goethe, which presents an episode from the epic Jerusalem Delivered by Torquato Tasso in the form of a series of dialogues between the knight Rinaldo, who has been enchanted by the witch Armida, and his fellow knights, who are calling him back to the path of duty.

The work is scored for piccolo, two flutes, two oboes, two clarinets, two bassoons, two horns, two trumpets, three trombones, timpani, tenor solo, four-part men's chorus, and strings.

The composer conducted, with the tenor Gustav Walter, a student chorus numbering 300, and the Court Opera orchestra.

It has never been popular, but is interesting on a number of counts, not least because it may give the closest idea of what an opera by Brahms would have sounded like.