There is no certain mention of the "Meditations" until the early 10th century. The historian Herodian, writing in the mid-3rd century, makes mention of Marcus' literary legacy, saying "He was concerned with all aspects of excellence, and in his love of ancient literature he was second to no man, Roman or Greek; this is evident from all his sayings and writings which have come down to us", a passage which may refer to the "Meditations". The "Historia Augusta"'s biography of Avidius Cassius, thought to have been written in the 4th century, records that before Marcus set out on the Marcomannic Wars, he was asked to publish his "Precepts of Philosophy" in case something should befall him, but he instead "for three days discussed the books of his "Exhortations" one after the other". A doubtful mention is made by the orator Themistius in about AD 364. In an address to the emperor Valens, "On Brotherly Love", he says: "You do not need the exhortations () of Marcus." Another possible reference is in the collection of Greek poems known as the "Palatine Anthology", a work dating to the 10th century but containing much earlier material. The anthology contains an epigram dedicated to "the Book of Marcus". It has been proposed that this epigram was written by the Byzantine scholar Theophylact Simocatta in the 7th century.