The Jacksonian Era 125dition that landed at Vera Cruz and swept inland to Mexico City. On
September 14 , 1847 , American troops captured the capital and Scott ac-
cepted its formal surrender by the city council. Meanwhile John C.
Frémont, captain of an engineering corps, arrived on an exploring
expedition in California and upon hearing that the United States had
declared war against Mexico helped a band of frontiersmen proclaim
the inde pendence of California. At first they set up the Bear Flag Re-
public, but then they raised the Stars and Stripes.
At about the same time Colonel Stephen W. Kearny, stationed at
Fort Leavenworth, Kansas, was ordered to invade New Mexico. He
arrived at Santa Fe in August, forced the retreat of a Mexican force
that was more than twice the size of his own army, and proclaimed
New Mexico a territory of the United States. He then proceeded west,
where he joined Frémont and completed the conquest of California.
In an effort to end the war as quickly as possible, Polk dispatched a
clerk in the State Department, Nicholas Trist, to Mexico as his peace
commissioner. Trist succeeded in producing the Treaty of Guadalupe
Continental expansion of the United States