Brahms was rehearsing his F minor piano quintet.

But when they reached the Andante, the strings played too fast to suit Brahms.

This had happened once before in an early rehearsal of the same work, and the composer had discovered a tactful way of handling the situation.  Instead of criticizing, he called: "Just a moment, please.  Something seems to be a little wrong here!"  He made a great pretense of putting on his glasses and examining the score.  "h'm, h'm," he grunted.  "I see I've marked that passage wrong!" Taking out his pencil he carefully wrote in "Meno Mosso" – less fast.  The others took the hint and finished the movement in the correct tempo.

When the quintet was finished they started on the G major sextet – the famous "A G A D E" sextet, which had been published that spring.  By now the musicians were so absorbed that they were no longer conscious of time or fatigue.  Hegar's servant-girl brought in platters of cold meat and rye bread, with chunks of rich Swiss cheese and steins of local beer.  Absent-mindlessly the men reached for food and continued with their playing, stopping only occasionally to call for more beer.

Brahms suddenly looked at his watch. "Heavens!" he cried.  "It's past midnight.  And my lodgings are far away from here, on the other side of town."

"You must stay with me for the rest of the night," Hegar insisted.  "And you, Dr. Billroth, your home is a long way off too -" He stopped short in dismay.  "Only – well, as a matter of fact I have nothing but one sofa to offer the two of you!"

Brahms laughed.  "That doesn't matter a bit.  I can sleep perfectly on the floor.  Here -" he pulled a cover from the couch, rolled himself in it, and slid under the grand piano.

Nothing would budge him from the spot.  In fact, while the others were still arguing, he began to snore peacefully.

The next morning he insisted that he had never had a better sleep!

Source: Goss, Madeleine & Schauffler, Robert (1943) Brahms The Master. New York: Henry Holt and Company, pp.210-212.