Dionysius of Byzantium (Διονύσιος ὁ Βυζάντιος) was a Greek geographer active in the 2nd century CE, likely during the reign of Emperor Hadrian. He is known only as the author of a work on the Bosporus Strait, and no details of his life beyond his name and origin survive [1].

His sole known work is the Anaplous Bosporou (Ἀνάπλους Βοσπόρου), or Peri tou Bosporou (Περὶ τοῦ Βοσπόρου), meaning "Voyage up the Bosporus" or "On the Bosporus." The text survives fragmentarily, primarily through a later epitome [1][2].

Dionysius’s significance stems from his detailed, periplus-like description of the Thracian Bosporus. His work provides valuable topographical, historical, and mythological information about the strait’s landmarks during the Roman era, making it an important source for the historical geography of the region [1][2]. The text exemplifies the antiquarian interests of the Second Sophistic period [1].

Sources 1. Oxford Research Encyclopedia of Classics: https://oxfordre.com/classics/view/10.1093/acrefore/9780199381135.001.0001/acrefore-9780199381135-e-2232 2. ToposText: https://topostext.org/people/1410