The Scythians, who called themselves Scoloti, as Herodotus further tells us, had previously dwelt in the east, and afterwards marched to the west, under the pressure of the Massagetæ. But Aristeas related that the Massagetæ had not driven out the Scythians, but the Arimaspians had driven the Issedones out of their land, and then the Issedones had expelled the Scythians. The Scoloti dwelt to the west of the land of the Sarmatians, on the western bank of the Tanais. Their territory extended along the shore of the Mæotis and Pontus, as far as the mouths of the Ister (Danube). This, the largest of all rivers "which we know," was said to flow down from the Celts, the nation in the extreme west, through the whole of Europe, till it finally reached the land of the Scythians, where it ran into the Pontus by five mouths.[473] The peninsula on the west side of the Mæotis, _i.e._ the Crimea, also belonged, so far as it was level, to the Scyths; but the Tauri dwelt on the mountains in the south-west. The reach from the mouth of the Don as far as the mouths of the Danube is the length of the land of the Scythians; the breadth Herodotus puts at twenty days' journey, _i.e._ 500 miles, if you go from the Pontus into the main-land to the north. According to this the territory of the Scoloti extended from the sea upwards in the east about as far as the bend of the Don to the south, and on the Dnieper as far as the rapids in this river; _i.e._ it comprised the land of the Cossacks on the west of the Don, and the steppe, and further to the west the plains of Moldavia, as far as the Carpathian range.[474] Like the land of the Sarmatians, the land of the Scoloti was one vast plain, without trees, with the exception of a strip of forest which extended from the sea on the left bank of the Borysthenes (Dnieper) from three to four days' journey up the river, but rich in grass, as it was watered by large rivers.[475] To the west of the Tanais the first river was the Borysthenes, the largest of the Scythian rivers, flowing down through the land; and the soil by the river was so good, that when sown it produced the best corn, and where it was not sown there stood tall grass. Further to the west the Hypanis (Bug) flowed out of a lake, round which pastured white horses, through Scythia to the Pontus; this river had a course of only nine days' journey (225 miles), while the Borysthenes was navigable for fourteen days' journey from the mouth.[476] Still further to the west was the Tyras (Dniester), which also flowed out of a lake; by these lakes are doubtless meant the marshes in the upper course of the Bug and Dniester.