This was the condition of the country when explored by the early French navigators, and when a century later it became the field for British and American adventurers. There was a reason for this desertion of a region rich in all that was dear to the red man. The river was the warway down which silently and swiftly floated the canoe fleets of a fierce, relentless, and invincible enemy. That the dreaded devastators of the country, when it was occupied by the ancient race, had made their invasions from the northward by way of the great stream, is suggested by the numerous lookout or signal mounds which crown the hills on either side of the valley, occupying the most advantageous points of observation. The Indians who dwelt in the territory included in the boundaries of Ohio had, when the white men first went among them, traditions of oft repeated and sanguinary incursions made from the same direction, and dating back to their earliest occupation of the country. History corroborates their legends, or at least those relating to less ancient times. The Iroquois or Six Nations were the foes whose frequent forays, made suddenly, swiftly, and with overwhelming strength, had carried dismay into all the Ohio country and caused the weaker tribes to abandon the valley, penetrated the interior and located themselves on the upper waters of the Muskingum, the Scioto, the Miamis, and the tributaries of the lake, where they could live with less fear of molestation. The Six Nations had the rude elements of a confederated republic, and were the only power in this part of North America who deserved the name of government.[5] They pretentiously claimed to be the conquerors of the whole country from sea to sea, and there is good evidence that they had by 1680 gained a powerful sway in the country between the great lakes, the Ohio and the Mississippi, and were feared by all the tribes within these limits. The upper Ohio was called by the early French the River of the Iroquois, and was for a long time unexplored through fear of their hostility.