As the American minister to the court of Napoleon, Livingston reached France in November, 1801. President Jefferson had already heard a rumor of the retrocession of Louisiana by Spain to France, and had given it little heed. He had cheerfully acquiesced in Spain's occupation of New Orleans, and after its retrocession to France he talked pleasantly of securing West Florida through French influence. "Such proof on the part of France of good will toward the United States," he wrote Livingston, in September, 1801, "would contribute to reconcile the latter to France's possession of New Orleans." But when, a year later, a French army, commanded by Leclerc, Napoleon's brother-in-law, had devastated St. Domingo and aroused the hostility of American merchants and ship-masters by his arbitrary treatment, Jefferson sensed the danger of having Napoleon for a next-door neighbor on the Mississippi. In a moment his tone changed from one of peace to a threat of war. "The cession of Louisianan to France," he declared, in a letter to Livingston, April 16, 1802, "works most sorely on the United States. There is on the globe one single spot, the possessor of which is our natural and habitual enemy. It is New Orleans. France, placing herself in that door, assumes to us the attitude of defiance. The day that France takes possession of New Orleans fixes the sentence which is to restrain her forever within her low-water mark. It seals the union of two nations, who in conjunction can maintain exclusive possession of the ocean. From that moment we must marry ourselves to the British fleet and nation."