On the ninth of April the French explorer René Robert Cavelier, Sieur de la Salle, and his tiny flotilla of Frenchmen and Indians reached the end of their six-week journey down the Mississippi. La Salle and his companions slid their canoes onto the shore just above the spot where the great river broadened into the Gulf of Mexico, and there, while the Indians watched, mystified, they ceremoniously planted a cross and an ornate column bearing the arms of France and the name of their king, Louis XIV.

“On that day,” wrote the historian Francis Parkman, “the realm of France received on parchment a stupendous accession. The fertile plains of Texas; the vast basin of the Mississippi, from its frozen northern springs to the sultry borders of the gulf; from the woody ridges of the Alleghenies to the bare peaks of the Rocky Mountains—a region of savannas and forests, sun-cracked deserts and grassy prairies, watered by a thousand rivers, ranged by a thousand warlike tribes, passed beneath the scepter of the Sultan of Versailles, and all by virtue of a feeble human voice, inaudible at half a mile.”