Partly-printed DS as president, one page, 8 x 10, March 23, 1842. President Tyler authorizes and directs the "Secretary of States to affix the Seal of the United States to a letter to the President of the Mexican Republic, accrediting Waddy Thompson as Envoy Extraordinary and Minister Plenipotentiary of the U. States." In fine condition, with light soiling to the edges. Waddy Thompson, Jr., of South Carolina served in the House of Representatives from to 1841, after which he was appointed by President Tyler as US minister to Mexico, where he served from 1842 to 1844. Thompson quickly learned enough Spanish to make his first speech to Mexican cabinet members in their own language, and became friendly with Mexican president Antonio Lopez de Santa Anna. He successfully negotiated the release of 300 Texan prisoners (saving 159 of them from execution), persuaded Mexico to permit American immigration to California, concluded some commercial agreements, and seriously attempted to negotiate the peaceful cession of California to the United States. A significant diplomatic document with relevance to Mexican-American relations in the mid-19th century.