Ygnacio Comonfort, a Mexican statesman, born in Puebla, March 12, 1812, killed near San Luis Potosi, Nov. 13, 1863. He entered the Jesuit college at Puebla in 1826, became a captain of cavalry in 1832, and took part in the revolution of that year. In 1834 he was made prefect and military governor of the district of Tlapa; in 1842 he was elected member of the national congress, but this was soon dissolved by Santa Anna, and Comonfort resumed his functions in Tlapa. In 1846 he was reelected to congress, but this congress was dissolved by Paredes, and the liberals instigated the revolution of August, 1846, in which Comonfort took a conspicuous part. Appointed third alcalde of the capital, and afterward prefect of western Mexico, he relinquished these posts to engage in the war with the United States; and on Santa Anna's dissolving the army and leaving the capital open for the Americans, Comonfort commenced organizing guerillas in the west, when he was summoned to the congress of Queretaro, where a treaty of peace was concluded with the United States. He was now chosen senator by his native state, and served in this capacity till 1851. In 1852-'3 he was the representative in congress of the state of Guerrero, and acted as custom-house director of Acapulco and other places until Santa Anna's return to power, when he was dismissed.

He now joined Alvarez, and proclaimed the plan of Ayutla, March 11, 1854. Repairing to New York, he raised funds to carry on the war, and on his return took a prominent part in the campaign, at the end of which, in 1855, Santa Anna was compelled to abdicate. Alvarez assumed the supreme government, but soon delegated his authority to Comonfort, who became provisional president, Dec. 11, 1855. He met with strenuous opposition on the part of the clergy, the army, and the large body of the conservative party. The junta of Zacapoastla declared itself on Dec. 19 against the president, and a little later the seat of revolution was transferred to the city of Puebla. Over 5,000 men assembled there, in February, 1856. Oomonfort marched against the insurgents, and having forced them to surrender, he promulgated on March 31 a decree ordering the confiscation of the property of the church, which was followed on June 28 by another decree forbidding the clergy to hold landed estate. The clergy labored to undermine the government, and revolts broke out in Puebla in October, 1856, and afterward in San Luis and other places; and although they were quelled, the country remained in a distracted condition.

The congress which assembled Feb. 5, 1857, drew up a new constitution, which was promulgated March 11. This vested the legislative power and the control over religious and military affairs exclusively in congress. Comonfort was eventually constrained, in October, 1857, to apply for extraordinary powers. These were granted by congress Nov. 4, and he was proclaimed constitutional president Dec. 1. Opposed by the clergy and the army, he could only depend upon the brigade of Gen. Zuloaga, which was attached to him personally. By a pronunciamiento at Tacubaya, Dec. 17, this brigade declared itself against the new constitution, and appointed Comonfort chief of a new government; but by a new pronunciamiento of Jan. 11, 1858, they discarded him altogether, and the insurrection which broke out on that day in the capital led to a bloody struggle of several days. Appointing Juarez, president of the supreme court, provisional president, Comonfort vainly attempted to regain his authority by force of arms. On the morning of Jan. 21 the capital was in the hands of the insurgents.

The house of representatives, convoked on the same day by Zuloaga, appointed that general provisional president, while Juarez convened a congress at Guanajuato to guard the rights of Comonfort. The latter in the mean time, deserted by his soldiers, took his departure from Mexico in February, 1858, and repaired to the United States, and afterward went to France. Juarez, having triumphed over Miramon and the church party, was chosen president in 1861. Shortly after the close of 1861 Comonfort returned to Mexico, and offered his services to Juarez, by whom he was appointed commander of the army. He was on his way from Mexico to San Luis Potosi when he was murdered by banditti.