Dionysius could find, in the authorities whom he consulted, no definite information about the life of Isaeus. The dates of his birth and death are unknown; we cannot, as Dionysius observes, say what were his political opinions, or even whether he had any at all.[153] We are even in doubt as to his birthplace; some authorities called him an Athenian, others a Chalcidian. The suggestion that he may have been the descendant of an Athenian who settled in Chalcis as a _cleruch_ is plausible, but without any authority.[154] The inference, from the fact that he took no part in public life, that he was probably an alien, is not justifiable. The fact that, whether an Athenian or not, he never spoke at any of the great national assemblies, where rhetoricians from all Greek countries gave displays, seems to argue that he had no ambition for personal distinction as an orator, but was content to be a professional writer of speeches. There is a legend that the young Demosthenes, impressed by the effectiveness of Isaeus’ oratory, induced the latter to live in his house and train him thoroughly in all the arts of the forensic speech-writer; it is even said that the earliest speech of Demosthenes, against Aphobus, was in reality composed by his master. The authority for these tales is quite insignificant, but the influence of Isaeus on Demosthenes was nevertheless considerable, whether or not they came much into personal contact. Dionysius records, on the authority of Hermippus, that Isaeus ‘was a pupil of Isocrates and a teacher of Demosthenes, and came into close contact with the best of the philosophers.’[155] There is no evidence that he was ever a companion of Socrates, since his name is not anywhere mentioned by Plato. His earliest speech (_On the Estate of Dicaeogenes_) is assigned with some probability to the year 390 B.C., and his latest (_On the Estate of Apollodorus_) to 353 B.C.