Seven years before he invaded Dauphin Island and claimed it for the U.S. from the Spanish, General James Wilkinson was deeded Dauphin Island by Forbes & Co. from Mobile:

(from TARNISHED WARRIOR  http://penelope.uchicago.edu/Thayer/E/Gazetteer/People/James_Wilkinson/JACTAR/11*.html

"Wilkinson resolutely argued that Mobile and Pensacola should be quickly occupied in order to prevent their use as hostile bases for operations against Louisiana; in fact, New Orleans was constantly menaced so long as they remained in the hands of the Spaniards, who were then allied with the English in a war with Napoleon. Personal reasons possibly abetted Wilkinson's strategic conclusions. In 1806 Forbes & Co., a great English trading house in the Floridas, had turned over to him, for an unknown consideration, Dauphin Island at the mouth of Mobile Bay. The company may have been merely a blind to hide a payment that the Spanish Crown wished to make to its old-time pensioner. No matter what induced the transfer, Wilkinson knew the island would increase greatly in value once it became a part of the federal domain. He could not foresee that his title would be disallowed ultimately by United States commissioners, strangely enough on the ground that he was not a Spanish subject at the time that the tract was acquired. He did not dare to turn over to them a paper that he had drawn up and signed in 1787, a paper Miro had accepted as equivalent to an oath of allegiance to the King of Spain."