See Epigram xxx.:-
Mallius indulget somno noctesque diesque:
Insomnis Pharius sacra, profana, rapit.
Omnibus, hoc, Italae gentes, exposcite votis,
Mallius ut vigilet, dormiat ut Pharius.
Hadrian was a Pharian (of Alexandria). See his public life in Godefroy, Cod. Theodos. tom. vi. p. 364. Mallius did not always sleep. He composed some elegant dialogues on the Greek systems of natural philosophy (Claud. in Mall. Theodor. Cons. 61-112).