John C. Frémont John Charles Frémont or Fremont ( January 21 , 1813July 13 , 1890 ) was an American military officer , explorer , and politician who became the first candidate of the anti-slavery Republican Party for the office of President of the United States .
John C. Frémont John Charles Frémont or Fremont ( January 21 , 1813 -- July 13 , 1890 ) was an American military officer , and explorer . He was the first candidate of the anti-slavery Republican Party for the office of President of the United States in 1856 .