William Walker (May 8, 1824 – September 12, 1860) was an American physician, lawyer, journalist and mercenary, who organized several private military expeditions into Latin America, with the intention of establishing English-speaking colonies under his personal control, an enterprise then known as "filibustering." Walker usurped the presidency of the Republic of Nicaragua in 1856 and ruled until 1857, when he was defeated by a coalition of Central American armies. He was executed by the government of Honduras in 1860.