Reform War between Liberals and Conservatives (1857–1861)

1. Constitution of 1857 is ratified

   Feb 5, 1857Labels: Constitution of, Mexican Liberals, Catholic Church

   Mexico ratified a new liberal constitution that expanded individual rights and limited long-standing legal privileges (called fueros) for the Church and the army. The new constitutional project sharpened conflict between Liberals who wanted secular reform and Conservatives who defended traditional institutions. This constitutional break set the stage for a civil war over who would control the Mexican state.

   • Britannica
   • 1857 Constitution

2. Plan of Tacubaya rejects the constitution

   Dec 17, 1857Labels: Plan of, Conservative Faction, Ignacio Comonfort

   Conservative forces issued the Plan of Tacubaya to nullify the 1857 Constitution and call for a new one. President Ignacio Comonfort initially aligned with the plan, which deepened the political rupture rather than calming it. The plan quickly became the trigger for armed conflict between rival governments claiming legitimacy.

   • Plan Tacubaya
   • Reform War

3. Juárez becomes constitutional president

   Jan 11, 1858Labels: Benito Ju, Supreme Court, Liberal Government

   After Comonfort resigned and left the capital, constitutional succession placed the head of the Supreme Court, Benito Juárez, at the head of the Liberal government. Conservatives organized a rival government in Mexico City, creating two competing national authorities. This split formalized the conflict that became known as the Reform War (also called the Three Years’ War).

   • La Reforma
   • Reform War

4. Battle of Salamanca favors Conservative forces

   Mar 9, 1858Labels: Battle of, Conservative Army, Guanajuato

   Early in the war, Conservative armies won important battlefield successes, including the Battle of Salamanca in Guanajuato. The defeat forced Liberal forces to retreat and highlighted the Conservatives’ early advantage in trained troops and commanders. These early losses pushed the Liberal government to rely more heavily on regional support and secure supply routes.

   • Salamanca 1858
   • Reform War

5. Reform Laws begin with church property nationalization

   Jul 12, 1859Labels: Reform Laws, Church Property, Liberal Government

   From Veracruz, the Liberal government issued major Reform Laws aimed at building a secular state and breaking the Church’s economic power. A key step was the law nationalizing ecclesiastical property, which sought to transfer Church holdings to the nation and support the war effort. These measures made compromise harder by tying the conflict to property, finance, and religion.

   • La Reforma
   • Reform War

6. Conservatives seek Spanish backing via Mon-Almonte Treaty

   Sep 26, 1859Labels: Mon Almonte, Conservative Leaders, Spain

   Conservative leaders negotiated the Mon-Almonte Treaty with Spain in an effort to gain financial and diplomatic support. The agreement was part of a broader pattern: both sides looked abroad for resources as the war dragged on. Even though the treaty did not ultimately take effect as intended, it added to international complications and debt pressures.

   • Mon Almonte
   • Reform War

7. Juárez signs the McLane–Ocampo Treaty with the United States

   Dec 14, 1859Labels: McLane Ocampo, Benito Ju, United States

   The Liberal government negotiated the McLane–Ocampo Treaty to obtain U.S. support by granting broad transit rights across parts of Mexico. The treaty became controversial because it was seen as trading sovereignty for survival during a civil war. The U.S. Senate ultimately refused to ratify it, limiting its legal effect.

   • McLane Ocampo
   • Reform War

8. Liberal victory at Loma Alta shifts momentum

   Apr 24, 1860Labels: Battle of, Liberal Forces, Zacatecas

   In 1860, Liberal forces began to win more consistently, including at Loma Alta in Zacatecas. These victories helped disrupt Conservative control of interior routes and weakened their ability to concentrate forces. The military balance gradually moved toward the Liberal side as they regained territory and cohesion.

   • Loma Alta
   • Reform War

9. Liberal victory at Peñuelas continues the advance

   Jun 14, 1860Labels: Battle of, Liberal Army, Central-North

   The Battle of Peñuelas in the central-north was another Liberal win during the 1860 campaign season. It further pressured Conservative forces by narrowing their room to maneuver and strengthening Liberal confidence and recruitment. By mid-1860, a series of such battles made the final confrontation more likely.

   • Pe uelas
   • Reform War

10. Battle of Silao weakens Miramón’s army

    Aug 10, 1860Labels: Battle of, Jes s, Miguel Miram

    At Silao in Guanajuato, Liberal forces under Jesús González Ortega (with Ignacio Zaragoza) defeated Conservative commander Miguel Miramón. The battle forced Conservative retreat and cost them weapons, artillery, and prisoners, reducing their ability to sustain the war. Silao helped open the way for a decisive endgame later in 1860.

    • Silao
    • QROO Efem rides

11. Battle of Calpulalpan ends major fighting

    Dec 22, 1860Labels: Battle of, Liberal Victory, Miguel Miram

    The decisive battle of the Reform War was fought at Calpulalpan, where Liberal forces defeated Miramón’s Conservative army. The defeat shattered organized Conservative military power and led their leaders to flee the capital or go into exile. Calpulalpan is widely treated as the war’s final major battle.

    • Calpulalpan
    • Reform War

12. Juárez enters Mexico City and restores Liberal government

    Jan 11, 1861Labels: Benito Ju, Mexico City, Liberal Restoration

    After the Liberal victory, Juárez entered Mexico City and reestablished national authority under the 1857 constitutional order. The war left the country financially and physically damaged, and some Conservative resistance continued in scattered areas, but the Liberal state project had won at the center. The Reform War’s outcome also shaped what followed: the weakened treasury and political divisions contributed to the crisis that soon drew European powers into Mexico.

    • Reform War
    • Calpulalpan