the Oregon region through seven degrees of latitude, while the Lewis and Clark expedition explored a continuous route from the Mississippi River to the Pacific Ocean, through the very center and by the central artery of the region in question. These two events together made the second ground of our claim to the region of the Oregon. Furthermore, they made possible for the first time that movement of population across our border into this adjacent and unoccupied territory which by the law of nations was essential to the validity of our title,—that immigration of American families upon which, in spite of every earlier attempt at settlement, the final settlement of the question of sovereignty was destined to wait.
Louisiana had been purchased by the United States from France, or, rather, from the First Consul, who at the time embodied in himself the government of France. Spain, however, though by a convention three years before the sale having agreed to retrocede the territory to France, had remained in possession almost to the day of its transfer to our government, so that possession of the territory virtually passed to the United States immediately from Spain. The transfer left Spain still with possessions within the present boundaries of the United States of vast extent and of immense value. East of the Mississippi were the Floridas, and west of that river was a great region extending from the ill-defined western boundary of Louisiana westward to the Pacific. These were conceded possessions of Spain. Besides, Spain was a claimant, on the grounds of discovery and exploration, of the Oregon country.
Spain had long claimed exclusive sovereignty over this region, with the right to forbid the encroachment of other nations, on the ground that it belonged to that region allotted to her by the bull of Pope Alexander VI.
