Dramatic, narrative LS, one page both sides, 8 x 12.75, June 12, 1818. Adams, as Secretary of State, sends an official communication to the Spanish envoy, Don Luis de Onis. In part: “[In a previous] letter in behalf of William D. Robinson, then detained as a prisoner at Campeachy … it was mentioned that eight other persons, citizens of the United States were confined with him and under similar circumstances…. Information has since then been received … that among them was William Thomson, who served with reputation as an Officer in the Army of the United States, during their late War with Great Britain; and who having landed on the Coast of Mexico in the year 1817, without joining in any act of hostility against Spain … was captured by a Spanish frigate and treated as a prisoner. Having made his escape from that ship … he surrendered himself on the express condition of being restored to Liberty…. After having been ten days at large he was again forcibly seized, sent far into the interior of the country, cast into a dungeon and here confined five months—after which he was transported, to be removed to Spain; and very recently was confined in the Moro Castle at the Havanna expecting very shortly to be sent from thence to Cadiz. For him and his fellow sufferers … I solicit again the interposition of your good offices with your Government … that … they may be immediately liberated on their arrival in [Spain].” The recipient, Don Luis de Onis (1769–1830), played a significant role in American history as coauthor of the Adams-Onis Transcontinental Treaty, which settled long-percolating land disputes between the United States and Spain. The treaty, concluded in February 1819 but not ratified until 1822, officially gave possession of Florida to the United States (in exchange for parts of Texas and five million dollars) and solidified a new western boundary that extended all the way to the Pacific Ocean. In fine condition, with several folds (tiny edge separations), a few stray ink spots to blank margin, and a touch of mild handling wear. Auction LOA John Reznikoff/PSA/DNA and R&R COA.
