The Promulgation, in 1812, of the Constitution of Cadiz provoked throughout Spain and her domains a bitter controversy between the opponents and the partisans of that liberal and innovative body of legislation. Among the supporters in Mexico City was José Joaquín Fernández de Lizardi (1776–1827), who, as soon as the Constitution went into effect there, established a sheet, El Pensador Mexicano (1812–14), with the avowed purpose of defending the new form of government and of praising its liberal provisions, particularly those granting freedom of the press and abolishing the Inquisition. His first article began with an exlamation: “¡Gracias a Dios y la nueva Constitutión que ya nos vamos desimpresionando de algunos errores que nos tenían enterrados nuestros antepasados!” But, in spite of the freedom of the press, the Viceroy ordered his arrest, and some months in jail dampened his enthusiasm; he continued, however, his periodical as well as its successor, the Alacena de Frioleras (1815), with articles of a less controversial nature, until the end of that year. Continually in difficulty with the censors after 1814, when the Constitution was abrogated by Ferdinand VII, he finally limited himself to the writing of fiction until the reestablishment of the Constitution in 1820. During this period he produced four novels, one of which, El Periquillo Sarniento (1816), is his masterpiece. While the characters and setting of this novel are definitely Mexican, with certain autobiographical elements, the mold in which it is cast is that of the Spanish picaresque. Like its prototype in general, the Periquillo is concerned with matters of a purely ethical nature; but this aspect of the novel is less impressive—in contrast, for example, with Alemán's Guzmán de Alfarache or the novels of Francisco Santos—than the wealth of ideas in regard to definite reforms that the author believes would contribute to the general welfare. These ideas, interwoven with incidents in the life of a picaro, did not originate with the author but reflect wide reading in many fields. To point out the sources of these ideas, and thereby fathom the intellectual background of Lizardi, is the object of this article.