During the two decades Santa Anna spent in exile, Mexico underwent one of the most violent and significant periods of its history. The Revolution of Ayutla led to the establishment of a liberal government that was tragically (and violently) divided between radicals and moderates. The presidencies of Juan Álvarez (October–December 1855) and Ignacio Comonfort (December 1855–January 1858) saw the beginning of what was to become known as the mid-century reform. With Benito Júarez and Miguel Lerdo de Tejada heading the Ministry of Justice and Ecclesiastical Affairs and that of Finance respectively, the laws of 23 November 1855 and 25 June 1856 were passed, bringing an end to all fueros, curtailing Church and military power, and confiscating all corporate-owned properties. The radical federal 1857 Constitution was also initiated. Almost inevitably, the conservative backlash, when it came, was especially violent. Following moderado president Comonfort's coup d'état against his own Congress on 17 December 1857, conservative General Félix Zuloaga overthrew the government with the troops of the Mexico City garrison on 11 January 1858, and all hell broke loose. From January 1858 to January 1861 the Civil War of the Reform was fought, with the conservatives holding onto the capital while Juárez became the president of the displaced legitimate liberal government established in Veracruz. Although Juárez's camp succeeded, after three years, in retaking the capital and winning the war, armed conflict soon broke out again, this time involving a European military intervention.
Coinciding with the eruption of the U.S. Civil War in April 1861 and nourished by a clique of conservative monarchist Mexican exiles,