Along the tributaries to the east of the Dnieper, lay the principalities of Tchernigof and of Novgorod-Severski. The ruling family of Tchernigof, the Olgovitchi, who traced their lineage to the illustrious Olga, were the most formidable rivals of Kief. East of these lay the double principality of Riazan and Murom, whose chief towns, respectively of the same name, the one on the Moskova, the other on the Oka, indicate their ancient principalities on the modern map of the empire. Westward, in the heart of mediæval Russia, inclosing within its boundaries the great forest of Okof, where rise the Volga, the Dnieper, and the Dwina, was the principality of Smolensk, all of whose towns were built on the banks of one or another of its great rivers. Its political importance lay in its control of nearly all the commerce of the realm. A government in the later divisions of the empire bears the name of the ancient principality. Near by was Toropets, capital of a secondary domain ruled over by two princes of renown, Mstislaf the Brave, and his son Mstislaf the Bold, glorious names in the history of their country. Further to the northeast, in the dense forests of the Volga and the Oka, lay the principality of Suzdal, with its towns, Suzdal, Rostof, Vladimir-on-the-Kliasma. This rugged region at the extremity of the Russia of the eleventh century, encircled by aboriginal Finn tribes, was destined in time to achieve a supremacy over all the other principalities, and to control the destinies of the nation. The Slavs of the Volga, mingling with the Finn tribes, Muromians, Meria, Tcheremisa, who, from being their enemies, were ultimately forced to become their subjects, produced a modified race, endowed with permanent, salient characteristics. The Russia of the steppes of the Dnieper, gave way gradually, and yielded its supremacy to the Russia of the forests of the Volga. From the principality of Suzdal emerged the Grand Duchy or Tsarate of Moscow, and from the Tsarate of Moscow arose Little and Great Russia, with which were included in the fifteenth century Red and White Russia, the Warm Soil, and other vast territories that combine to form the European portion of the modern empire. The principalities we have named presented a frontier against the untamed tribes of the steppes and of the forests. A northern system of frontier defences holding in check the Lithuanians, Letts, and Tchudi, was re-enforced by the powerful governments of Novgorod and Pskof, situated in the regions of Lake Ilmen and Lake Peïpus. Within the protection of these domains lay two secondary appanages, Polotsk and Mursk, the latter in the basin of the Dnieper. In southwest Russia lay Volhynia and Gallicia, or Red Russia, one of whose cities was Galitch. Gallicia was peopled by the White Kroats, a branch of the Danubian Slavs, who had affinities with the neighboring kingdoms of Poland and Hungary. Igor, Prince of Novgorod-Severski, is the hero of a Russian epic, that relates his expeditions.