Diogenes Laertius, Lives of the Philosophers
1.10.109 (on Epimenides, tr. R.D. Hicks):
One day he was sent into the country by his father to look for a stray sheep, and at noon he turned aside out of the way, and went to sleep in a cave, where he slept for fifty-seven years. After this he got up and went in search of the sheep, thinking he had been asleep only a short time. And when he could not find it, he came to the farm, and found everything changed and another owner in possession. Then he went back to the town in utter perplexity; and there, on entering his own house, he fell in with people who wanted to know who he was. At length he found his younger brother, now an old man, and learnt the truth from him.