He may have composed one of the most famous lullabies, but it seems that Johannes Brahms seldom enjoyed a peaceful night himself.
Evidence has emerged from a host of biographical references that the 19th-century composer suffered from obstructive sleep apnoea.
The common disorder, which was unknown to medical experts of the day, brings on sudden interruptions of breathing, heavy snoring, sleep deprivation and excessive daytime sleepiness.
Mitchell Margolis, a physician from Philadelphia, in the latest issue of the journal Chest, has found records of all of these symptoms in Brahms's personal history.
The most obvious symptom, that of habitual snoring, was never noted by a spouse as he never married.
However, George Henschel, a baritone who travelled with Brahms on a concert tour, remarked that Brahms's snoring once drove him from a shared room, as staying "would mean death to any hope of sleep".
Later in life, Brahms was often seen taking an afternoon snooze in the cafes of Vienna and was known to fall asleep at the table or theatre - the price of sleepless nights.
Margolis noted that the composer became obese, outgrowing his fur coat by 35, and averse to wearing a tie as his neck became so wide. Increased upper-body obesity is a predictor of sleep apnoea.
Brahms's prickly personality may be another indicator. He once remarked:
"If there is anyone here I have not offended, I apologise."
Irritability and depression are also typical of the personality changes that accompany the disorder.
While sleep apnoea may have blighted Brahms's life, it is possible it may have pushed him on to greatness.
Margolis said: "One wonders if the disorder contributed to lifelong alienation from friends and marriage, thereby indirectly nurturing his determined devotion to the creation of his immortal music."