Before the war, of which this was the grand sequel, a thin stream of English immigrants, chiefly from Virginia and North Carolina, under the lead of Daniel Boone, had crossed the mountains of North Carolina into Kentucky. This movement was central in what is commonly known as the Blue Grass Region, of which Lexington may be considered the pivot. After the war, a second and larger emigration, chiefly from New England, crossed over the Alleghanies to the head of navigation on the Ohio, whence it moved down that river to the Muskingum, and was central about Marietta. Here, then, we have two separate streams of population, belonging to the same sturdy Anglo-Saxon race, though originating in different sections of the young Republic, each taking along with it to its new home in the West the customs and traditions of its own section, and guided by instinct or destiny upon lines which, ere long, were to divide slave from free States. By an Act of Congress, known in history as the Ordinance of 1787, all that great block of wilderness country, into which this last emigration was setting, became one political division under the name of the North-west Territory.[3] The Act creating this territory also provided for making three States from it, and most wisely forbade that slavery should ever exist within its borders. Thus it was that the Ohio came to be not only a physical, but a political, dividing-line between the sections, which, now that the law of the land had fixed a limit slavery should not overstep, came to be designated as North and South, not, as formerly, from geographical situation only, but because the line had been thus sharply drawn between free and slave institutions. Each was now on trial before the world; each was now to show what it could do for human progress, under its own institutions, with its own means, and on its own chosen ground. It would seem as if this splendid acquisition of ours, this North-west Territory, now constituting the great heart and seat of power in the American Union, might well have filled the fullest measure of patriotic desire for territorial expansion. It was to be, however, but the cradle of a newer and more robust growth, as the original States had been for that just beginning at the centre. It was an empire in itself, comprising all those States now enclosed between the Mississippi, the Ohio, Pennsylvania, and the Great Lakes. Yet this whole tract held, in 1792, no more than ten thousand whites, settled in widely scattered spots, among sixty-five thousand wild Indians.