Marcianus, of Heraclea

Marcianus of Heraclea (Heraclea Pontica, on the Black Sea) was a Greek geographer of late antiquity, usually placed in roughly the late 4th or early 5th century CE, though his exact dates are uncertain. He is best known for the Periplus of the Outer Sea, a coastal survey describing the seas beyond the Mediterranean, drawing heavily on Ptolemy. He also compiled epitomes of earlier geographical works, including an abridgement of the Periplus of the Inner Sea by Menippus of Pergamon and a summary of the Geography of Artemidorus of Ephesus, helping preserve traditions that would otherwise be lost.