The Roman History · Amm. 16.5.4

Hereupon arose his custom of dividing his nights into three portions, one of which he allotted to rest, one to the affairs of the state, and one to the study of literature; and we read that Alexander the Great had been accustomed to do the same, though he practised the rule with less self-reliance. For Alexander, having placed a brazen shell on the ground beneath him, used to hold a silver ball in his hand, which he kept stretched outside his bed, so that when sleep pervading his whole body had relaxed the rigour of his muscles, the rattling of the ball falling might banish slumber from his eyes.

Ammianus Marcellinus · translated by C. D. Yonge · 1911 reprint
C. D. Yonge translation (preface dated February 1862); G. Bell and Sons, 1911; Project Gutenberg #28587
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