By late 1918, many German citizens were fed up with the war. There were major food shortages, and protests and rallies throughout the country. The population blamed Emperor Wilhelm II for the war and demanded his abdication. Most soldiers were tired of fighting as well and wanted the war to end.
On 9 November 1918, the emperor was forced to abdicate. People did not agree on who should take over, though. The established parties were afraid that the communist revolutionaries would seize power. To prevent this from happening, social-democratic politician Philipp Scheidemann proclaimed the republic that very afternoon.
A few hours later, communist leader Karl Liebknecht claimed that Germany was now a 'free socialist republic'. The result was a power struggle between the social democratic party and the communist party.
In January 1919, the unrest reached its peak. Left-wing workers declared a general strike, the Spartacus uprising. To prevent a left-wing radical revolution, the moderate social democrats called in the help of the army and the Freikorps to fight the revolutionairies in the streets. A Freikorps was an independent unit of voluntary soldiers. They were opposed against both the communists and the republic.
On 15 January, members of a Freikorps arrest the two leaders of the uprising, Karl Liebknecht and Rosa Luxembourg, and assaulted and murdered them. This ended the uprising, but the atmosphere remained turbulent for months afterwards.