(Maria Isabel Luisa), ex-queen of Spain, born in Madrid, Oct. 10, 1830. She is the eldest daughter of Ferdinand VII. and his fourth wife, Maria Christina. The question of her succession to the throne caused in Spain a bloody civil war. Her father, having no son, repealed (March 29, 1830) the Salic law, introduced into Spain by Philip V., and named the expected offspring of his fourth marriage to succeed him, thus excluding his brother Don Carlos, who was then heir presumptive by virtue of that law. Ferdinand dying Sept. 29, 1833, Isabella, then only three years old, was proclaimed queen. Don Carlos took up arms, supported by a large body of adherents, known as Carlists. The contest gradually assumed the worst form of civil war, the clergy taking sides with Don Carlos, while the queen's party was identified with that of the exaltados, liberals, or constitutionalists; the queen mother, who had taken the title of regent, having guaranteed a constitution to Spain. The young queen was supported by the majority of the people, and in 1834 it was almost unanimously agreed by the legislative cortes that Don Carlos and his descendants should be for ever excluded from the Spanish throne; a decree which was confirmed by the constituent cortes in 1836. Peace was virtually concluded at the end of August, 1839, at Vergara, by the convention between the Carlist general Maroto and Gen. Espartero, the most successful of the constitutionalist commanders, and Don Carlos fled to France. During the course of the struggle the queen regent vacillated between the two parties of moderados, or conservatives, and exaltados, or liberals.

The ministry of Mendizabal modified the constitution, enlarged the electoral law, and introduced other reforms; but the juntas, still dissatisfied, demanded the constitution of 1812, which was finally extorted by the insurrection of Madrid, June 18, 1837. The great insurrections of Barcelona and of Madrid in 1839 caused the flight of the queen mother into France (October, 1840). Espartero now became head of the government, and on May 8, 1841, was declared regent, but was finally compelled by an insurrection of the friends of Christina and the radicals to abdicate; the cortes, by advancing the majority of the queen 11 months, placed her on the throne, Nov. 10, 1843. Gen. Nar-vaez, who had placed himself at the head of the insurrection, became chief of the cabinet in 1844, and in the following year the constitution was modified in a reactionary sense. On Oct. 10, 1846, under the influence of Louis Philippe, she was married to her cousin, Don Francisco de Asis, and at the same time her sister Maria Ferdinanda Luisa was married to the duke of Montpensier. This alliance gave rise to sinister comments, and resulted in domestic unhappiness and in injurious reports in regard to the conjugal fitness of the king and the conjugal fidelity of the queen.

Isabella established alliances with Austria and Prussia, and in 1849 sent an army to aid the pope. An attempted assassination of the queen in 1852 was turned to account by the conservatives, who procured the dissolution of the cortes and the adoption of repressive measures. Several liberal generals having been banished, on June 28, 1854, Gens. O'Donnell and Dulce headed a military and civil insurrection in Madrid, and succeeded in reestablishing a liberal government. The queen mother fled again to France, and the queen proclaimed an amnesty, opened a new cortes, and legalized the sale of church property. In 1856 an attempted coup d'etat by O'Donnell, and the suppression of revolts in the south of Spain, gave the queen more power, and reestablished the constitution of 1845. This induced the most reactionary measures, which in turn brought about a year later the fall of the Nar-vaez cabinet and the formation of a more liberal ministry (October, 1857). A war with Morocco, undertaken by O'Donnell, was successfully terminated in April, 1860. The intervention in Mexican affairs jointly with the French, and under the lead of Prim, in 1861-'2, was speedily cut short by that general. Wasteful enterprises in Santo Domingo and against Peru and Chili proved entirely fruitless.

In 1865 Isabella was compelled by the resignation of her ministers to give her sanction to the bill repealing the law of 1861, by which the republic of Dominica was incorporated with the monarchy; and in the same year she ordered the sale of all the crown property, with the exception of the royal residences and entailed estates, for the benefit of the nation. In 1866, under the influence of the priests and a new Narvaez cabinet, she abolished freedom of the press and placed public instruction in the hands of the clergy. Insurrections, instigated and partly led by Prim, broke out in that and the following year in various parts of the country, but failed for want of organization. Gonzalez Bravo, the successor of Narvaez at the head of the cabinet, carried reaction still further, until in September, 1868, a revolt began at Cadiz which speedily spread over all Spain, and resulted in the queen's flight to France, with her children, her lover Marfori, and her chaplain Claret. (See Prim, and Serrano.) Napoleon III. put at her disposal the castle at Pau, whence she issued a proclamation to the Spanish people, protesting against the revolution.

On Sept. 29,1868, her deposition was declared at Madrid, and on Nov. 6 she took up her residence in Paris, where she has since remained, with the exception of an interval spent at Geneva during the Franco-German war. On June 25, 1870, she abdicated her claim to the throne of Spain in favor of her son, Alfonso Francisco de Asis Fernando, etc. (born Nov. 28, 1857), prince of As-turias, who assumed the title of Alfonso XII.