the Spanish king's ministers in Madrid secretly instructed Gálvez to sell the Americans desperately needed supplies. The British had blockaded the colonial ports of the Thirteen Colonies, and consequently the route from New Orleans up the Mississippi River was an effective alternative. Gálvez worked with Oliver Pollock, an American patriot, to ship gunpowder, muskets, uniforms, medicine, and other supplies to the American colonial rebels. Although Spain had not yet joined the American cause, when an American raiding expedition led by James Willing showed up in New Orleans with booty and several captured British ships taken as prizes, Gálvez refused to turn the Americans over to the British. In 1779, Spanish forces commanded by Gálvez seized the province of West Florida, later known as the Florida Parishes, from the British. Spain's motive was the chance both to recover territories lost to the British, particularly Florida, and to remove the ongoing British threat. On 21 June 1779, Spain formally declared war on Great Britain. On 25 June, a letter from London, marked secret and confidential, went to General John Campbell at Pensacola from King George III and Lord George Germain. Campbell was instructed that it was the object of greatest importance to organize an attack upon New Orleans. If Campbell thought it was possible to reduce the Spanish fort at New Orleans, he was ordered to make preparations immediately. These included securing from Vice-Admiral Sir Peter Parker as many fighting ships as the fleet at Jamaica could spare, gathering all forces in the province that could be assembled, recruiting as many loyal Indians as the Superintendent could provide, and drawing on His Majesty's Treasury through the Lords Commissioners to pay expenses. As an unfortunate twist of fate for Campbell, upon which his whole career was decided, the secret communication fell into the hands of Gálvez. After reading the communication from King George III and Germain, Gálvez, as Governor of Louisiana, swiftly and secretly mobilized the territory for war. Gálvez carried out a masterful military campaign and defeated the British colonial forces at Fort Bute, Baton Rouge, and Natchez in 1779. The Battle of Baton Rouge, on 21 September 1779, freed the lower Mississippi Valley of British forces and relieved the threat to the capital of Louisiana, New Orleans. In March 1780, he recaptured Mobile from the British at the Battle of Fort Charlotte. Gálvez's most important military victory over the British forces