(Ἀγαθήμερος), the son of Orthon, and the author of a small geographical work in two books, entitled (), addressed to his pupil Philon. His age cannot be fixed with much certainty, but he is supposed to have lived about the beginning of the third century after Christ. He lived after Ptolemy, whom he often quotes, and before the foundation of Constantinople on the site of Byzantium in A. D. 328, as he mentions only the old city Byzantium. (2.14.) Wendelin has attempted to shew that he wrote in the beginning of the third century, from the statement he gives of the distance of the tropic from the equator; but Dodwell, who thinks he lived nearer the time of Ptolemy, contends that the calculation cannot be depended on. From his speaking of Albion ἐν ᾗ στρατόπεδα ἵδρυται, it has been thought that he wrote not very long after the erection of the wall of Severus. This is probably true, but the language is scarcely definite enough to establish the point.