Adams performed well as secretary of state under President Monroe. He crafted the foreign policy doctrine that later bore the president’s name—the Monroe Doctrine. Historian Robert V. Remini writes in his 2002 biography of Adams, John Quincy Adams: “John Quincy Adams is arguably the greatest secretary of state to serve that office.” He helped negotiate the Adams-Onis, or Transcontinental Treaty of 1819, which established the western boundaries of the Louisiana purchase and solidified relations between the United States and Spain.