Dictionary of Greek and Roman Geography/Propontis
PROPONTIS (Πρωπονίς: Sea of Marmora), the sea between Thrace and Asia Minor, forming an intermediate sea between the Aegean and the Euxine, with the latter of which it communicates through the narrow strait of the Thracian Bosporus, and with the former through the Hellespont. Its ancient name Propontis describes it as " the sea be-
fore the entrance of the Pontus" or Euxine; while its modern name is derived from the island of Marmora, the ancient Proconnesus, near the western entranceof the sea. (Appul. de Mund. p. 6 ; Steph. B. s. v. (Πρωπονίς) The first authors who mention the Propontis under this name are Aeschylus (Pers. 876), Herodotus (iv. 85), and Scylax (pp. 28, 35); and Herodotus seems even to have made an accurate measurement of this sea, of which he states the length, to be 1400 stadia, and the breadth 500. Later writers such as Strabo (ii. p. 125) and Agathemerus (ii. 14), abandoning the correct view of their predecessor, state that the breadth of the Propontis is almost equal to its length, although, assuming the Propontis to extend as far as Byzantium, they include in its length a portion of the Thracian Bosporus. Modern geographers reckon about 120 miles from one strait to the other, while the greatest breadth of the Propontis from the European to the Asiatic coast does not exceed 40 miles. The form of the Propontis would be nearly oval, were it not that in its south-eastern part Mt. Arganthonius with the promontory of oseidion forms two deep bays, that of Astacus [Sinus Astacenus] and that of Cius [Cianus Sinus]. The most important cities on the coasts of the Propontis are: Perinthius, Selymbria, Byzantium, Chalcedon, Astacus, Cius, and Cyzicus. In the south-west there are several islands, as Proconnesus, Ophiusa and Alone; at the eastern extremity, south of Chalcedon, there is a group of small islands called Demonnesi, while one small island, Besbicus, is situated in front of the bay of Cius. (Comp. Polyb. iv. 39, 42; Strab. xii. p. 574, xiii. pp. 563, 583; Ptol. v. 2. § 1, vii. 5. § 3, viii. 11. § 2, 17. § 2; Agath. i. 13; Dionys. Per. 137; Pomp. Mela, i. 1, 3, 19, ii. 2, 7 ; Plin. iv. 24, v. 40 ; Kruse, Ueber Herodots Ausmessung des Pontus Euxinus, &c, Breslau, 1820.) [ L. S. ]