Thousand Days' War: The Colombian Conservative Party turns the tide of war in their favor with victory against the Colombian Liberal Party in the Battle of Palonegro.

The Thousand Days' War was a civil war fought in Colombia from 17 October 1899 to 21 November 1902, at first between the Liberal Party and the government led by the National Party, and later – after the Conservative Party had ousted the National Party – between the liberals and the conservative government. Caused by the longstanding ideological tug-of-war of federalism versus centralism between the liberals, conservatives, and nationalists of Colombia following the implementation of the Constitution of 1886 and the political process known as the Regeneración, tensions ran high after the presidential election of 1898, and on 17 October 1899, official insurrection against the national government was announced by members of the Liberal Party in the Department of Santander. Hostilities did not begin until the 11th of November, when liberal factions attempted to take over the city of Bucaramanga, leading to active warfare. It would end three years later with the signing of the Treaty of Neerlandia and the Treaty of Wisconsin. The war resulted in a Conservative victory, and ensured the continued dominance of the Conservative Party in Colombian politics for another 28 years. Colombia's political structure as a unitary state has not been challenged since.

The Colombian Conservative Party is a conservative political party in Colombia. The party was formally established in 1849 by Mariano Ospina Rodríguez and José Eusebio Caro.

The Colombian Liberal Party is a centre to centre-left political party in Colombia. It was founded as a classical liberal party but later developed a more social-democratic tradition, joining the Socialist International in 1999.

The Battle of Palonegro was a battle in the Santander Department of Colombia, that lasted from May 11—26, 1900, in the early days of the Thousand Days War. The commanding general of the Liberal armies, Gabriel Vargas Santos, ordered his troops to retire to Palonegro, near the city of Bucaramanga in the Santander Department of Colombia. After the battle, the war escalated, and became one of the most brutal conflicts in early 20th century South America.