Abraham Alfonse Albert Gallatin (January 29, 1761 – August 12, 1849) was a Swiss-American politician, diplomat, ethnologist and linguist. He was an important leader of the Democratic-Republican Party, serving in various federal elective and appointed positions across four decades. He represented Pennsylvania in the Senate and the House of Representatives before becoming the longest-tenured United States Secretary of the Treasury and serving as a high-ranking diplomat.
