Answer
The National Schism in the 1910s was essentially a civil war between the royalists, who supported King Constantine I of Greece, and the Venizelists, who supported Eleftherios Venizelos, a politician who had been prime minister several times. The schism began when the two sides disagreed over whether to support or oppose the Central Powers in World War I. The royalists supported the Central Powers, while the Venizelists supported the Allies.