Plutarch in his work (“Life of Alexander”, 8) mentions that Alexander the Great kept a special copy of the “Iliad” under his pillow while sleeping, with Aristotle’s commentaries. This was largely due to the love of the leader of this Greek epic and the character of Achilles.
According to Athenaeus (a Greek writer from the 2nd-3rd century CE), his father Philip preferred to hide a golden wine cup under his pillow during a nap.
In turn, in the Roman world, we know that e.g. adopted son of Emperor Hadrian and expected successor – Ceionius Commodus – read Apicius’ cookbook to sleep and “Amores” from Ovid.