PENA y PENA, Manuel de la (pain'-yah), president of Mexico, born in Tacuba, 10 March, 1789; died in the city of Mexico, 2 January, 1850. He studied in the seminary, was graduated in law, 16 December, 1811, and on 26 December, 1813, appointed attorney-general of the corporation of Mexico. In 1820 he was elected a member of the audiencia of Quito, but, on account of political events, could not take charge of that office, and filled provisionally a vacancy in the audiencia of Mexico. In April, 1822, he was given an appointment in the treasury, and on 21 October, Hurbide, who had proclaimed himself emperor, appointed him minister to Colombia, but he did not leave Mexico, on account of the fall of the empire. Two years afterward he was elected to the supreme court of justice. In 1837 he formed part of Bustamante's cabinet as minister of the interior, and the following year he was elected member of the supreme conservative power. This was a third power instituted in 1837, besides the legislative and executive powers, a sort of senate. It was abolished in 1838. He taught public law in the university and was president of the Academy of jurisprudence and rector of the College of lawyers. In 1841 he was a commissioner for the formation of the civil code. In 1843 he was appointed councillor of state and senator, but soon entered the cabinet again as secretary of state. On 26 September, 1847, as president of the supreme court, he took charge of the executive of the nation in Queretaro, and held it till 12 November, when congress elected Gem Anaya provisional president, but, as it failed to agree on the election of a constitutional president, Pefia took charge again on 8 January, 1848. During his government the American invasion took place, which was ended by the treaty of Guadalupe Hidalgo. On 3 June he delivered the government to the constitutional president, General Herrera (q. v.), and returned to the presidency of the supreme court, which he held till his death. He published " Lecciones de practica forense Mexicana" (Mexico, 1842).