From 1865, Guatemala had been under the dictatorship of Vicente Cerna. Cerna’s persecution of liberal party members, eventually resulted in the Liberal Revolution, which began with a revolt in Guatemala City on June 30th 1871.
One key action after the revolution had toppled Cerna, was the modernisation of the armed forces.
For a period, this holiday was called Revolution Day, but it’s impact on the armed forces, led it to become the official holiday commemorating the role of the army in protecting and serving the nation.
As you might imagine, the day is marked with a military parade. All branches of the armed forces participate in the parade.