Leonardo Marquez, a Mexican general, born in the city of Mexico about 1818. Entering the army at an early age, he was engaged in several battles in the valley of Mexico against the American army in 1847. He headed a pronunciamiento in the state of Guanajuato, Feb. 10, 1849, declaring the election of President Ilerrera illegal, and recalling Santa Anna to the government. The movement was suppressed, and Marquez was made prisoner, but he was soon set at liberty. After the accession of Santa Anna in 1853, Marquez was intrusted with important commands in the war against Alvarez and Comonfort; and after the flight of Santa Anna, in August, 1855, he continued for two years to maintain a guerilla warfare in his behalf. During the war of reform he became one of the chief military leaders under Presidents Zuloaga and Comonfort. He defeated at Tacubaya, April 11, 1859, the liberal forces, which laid siege to the capital under Degollado, thus saving Miramon from imminent danger, but stained his victory by the execution of his prisoners, including several medical students and other non-combatants. This deed, of which he divides the responsibility with Miramon, is known as the massacre of Tacubaya, and brought upon Marquez an odium -from which he has never recovered.

After the triumph of Juarez, Marquez continued an irregular warfare in 1861, during which he again stained his reputation by the execution of his prisoners, Generals Degollado and Valle, and of the prime minister Ocam-po. For these deeds he was declared an outlaw by congress, and a price was set on his head. He united his forces with the French invaders in 1862, and favored the elevation of Maximilian to the throne; but that prince was unwilling to accept his military services, and gave him an honorable exile as minister to Turkey. In October, 1866, he returned to Mexico without permission, and was appointed to the command of a division. When Maximilian set out for Queretaro in 1867, Marquez was left in command of the city of Mexico, which he defended for three months against Gen. Porfirio Diaz, not capitulating till June 21, two days after the execution of Maximilian. He secreted himself for several weeks, and at last escaped to Havana. He is one of three persons expressly excluded from the amnesty of 1870. He has published two pamphlets in defence of his military record.