About 91 km E-SE of Istanbul at the head of the Gulf of Nicomedia; the modern Ismit. Nicomedia was founded about 264 B.C. by Nicomedes I of Bithynia (Strab. 12.4.2) on the site of the Greek colony of Olbia. First the capital of the Bithynian kingdom (Memnon 20.1), and later of the Roman province of Bithynia, Nicomedia was astride the great highroad connecting Europe and the East, and was a port as well; Nicaea was its rival. It is mentioned frequently in the Letters of the younger Pliny (esp. Book 10) and by Dio Cassius (esp. in Books 73, 78, and 79). Sextus Pompeius, in flight, halted there in 36 B.C. (Dio Cass. 49.18.3); a few years later Octavian allowed the Bithynians to consecrate a precinct to his name in the town (Dio Cass. 51.20.7). Passages in Dio Chrysostom (Or. 38, and 47.16) evoke a prosperous and growing metropolis, and the city's buildings and water supply came repeatedly to the attention of Trajan and Pliny when the latter was governor of Bithynia. Emperors visited and wintered there (Dio Cass. 78.18-19, and 79.8 and 35), a garrison existed (Plin. Ep. 10.74), and the city, a major one in later antiquity, housed a statio of the imperial post and a fleet headquarters. Sacked by the Goths in A.D. 256, Nicomedia became, in Diocletian's time, the much adorned E capital of the Empire (Lactant. De mort. pers. 17.2-9), but the foundation of Constantinople and severe earthquakes in the 4th and 5th c. greatly reduced its importance (Amm. Marc. 22.9.3). Something of a renaissance resulted from the care of Theodosius II (A.D. 408-50). There is a varied and important coinage.
Little excavation has taken place, and much that could be seen in the last century is no longer visible. Vestiges of a Hellenistic building of unknown function have come to light. Along the contours of Nicomedia's hilly site exist stretches of the Roman walls (with Byzantine and Turkish restorations and additions); they are of late antique construction--;rows of brick alternating with rows of stone. At their NE limit are the remains of a high tower, and beside this is the gate to the road leading N to the Euxine. Parts of the harbor wall, which could be seen until a generation ago, were of typically Roman brickwork. Marble elements of a very large nymphaeum of the 2d c. A.D. have been found (Istanbul street), and E of the city there are the remains of two if not three aqueducts (Plin. Ep. 10.37), one of which appears to rest on foundations of Hellenistic date (Libanius, Or. 61.7.18, speaks of the copious supply of water to Nicomedia in the 4th c. A.D.). In the E district of the city, at the old Jewish cemetery, there are the ruins of a late Roman cistern of considerable size, built of reduplicated bays roofed with saucer domes of brick carried on piers. Major ancient drains were in use in Ismit until 1933.
Inscriptions, coins, and texts record, among others: a Temple of Roma (29 B.C., the meeting place of the provincial assembly); a Temple of Demeter, and satellite structures, in a large rectangular precinct on the hill visible from the harbor; a theater nearby; a colonnaded street (a few bits were once seen) probably leading from Demeter's precinct to the harbor; a forum (Plin. Ep. 10.49); a Temple of Isis and a hall for the Gerusia (10.33); a Temple of Commodus (Dio Cass. 73.12.2); and, for Diocletian, a palace, an armory, a mint, and new shipyards were built. Evidence of necropoleis abounds, and about 8 km N of the city are tumuli which may be the tombs of the Bithynian kings. One coin hails Hadrian as Restitutor Nicomedine.
Pliny and Justinian and Suleiman the Magnificent after him) hoped to finish the canal, long proposed, between the Propontis and the Euxine via Nicomedia, the Sabanja Gol (Lake Sunonensis in Amm. Marc. 26.8.3) and the Sangarios system (E p. 41 and 61); the project was never realized. There is a modest museum in the town, and objects from Nicomedia can be seen in the archaeological museums of Istanbul and Izmir. (W. L. MAC DONALD) Wikidata ID: Q209349
Info: Princeton Encyclopedia
(Princeton Encyclopedia of Classical Sites, from Perseus Project)