The kingdom of Bithynia held a considerable place among the minor monarchies of Anatolia. The coins of the Bithynian kings depict their regal portraits in a highly accomplished Hellenistic style. Nicomedes IV, the last king of Bithynia, was defeated by Mithridates VI of Pontus, and, after being restored to his throne by the Roman Senate, bequeathed his kingdom by will to the Roman Republic in 74 B.C. Under Rome, the boundaries of Bithynia frequently varied and it was sometimes united with Pontus. For securing communications with the eastern provinces, the monumental Bridge across the river Sangarius was constructed around 562 AD. Troops frequently wintered at Nicomedia. The most important cities were Nicomedia, founded by Nicomedes, and Nicaea. The two had a long rivalry with one another over which city held the rank of capital. At a much earlier period the Greeks had established on the coast the colonies of Cius (modern Gemlik); Chalcedon (modern Kadiköy), at the entrance of the Bosporus, nearly opposite Byzantium (modern Istanbul) and Heraclea Pontica (modern Karadeniz Eregli), on the Euxine, about 190 km east of the Bosporus.