The War of Reform, a Mexican civil war fought from December 1857 to January 1861, begins with a coup of generals representing the conservative section of the elite.

They refuse to recognize the reformist Constitution of 1857, and issue a decree overturning it, the Plan de Tacubaya.

The coup is opposed by liberals and others who are dissatisfied with the Catholic Church's stronghold on government and economic affairs, and disgusted by the extra-legal actions of the generals.

Civil unrest ensues, and quickly turns into a civil war.

The war ends with the Liberals being victorious and President Benito Juárez moving his administration to Mexico City.

After Congress completes the task of voting in a new constitution, called the Constitution of 1857, it calls for elections of the federal government, as well as of the states.

The legislature of each state establishes its own constitution, based on the principles of the federal constitution.

The first Constituent Congress functions under the principles of the Constitution of 1857.