f the Balkan wars in 1912 and 1913 (in which the Ottomans lost all Balkan land), a common border with Serbia was established, with Shkodër being awarded to a newly created Albania. In World War I in 1914 Montenegro sided with Serbia against the Central Powers, suffering a full scale defeat to Austria-Hungary in early 1916. In 1918 the Allies liberated Montenegro, which was subsequently merged with Serbia.
Unification and Christmas Uprising
During World War I (1914–1918) Montenegro was allied with the Allied Powers. From 15 January 1916 to October 1918, Montenegro was occupied by Austria-Hungary. During occupation, King Nicholas fled first to Italy and then to France, and the government transferred its operations to Bordeaux. When the Allies liberated Montenegro, the Podgorica Assembly was convened and voted to ban the king from returning and to unite the country with the Kingdom of Serbia on 1 December 1918. In the Christmas Uprising, a large part of the Montenegrin population, known as the Greens, rebelled against this decision to unify with Serbia and, led by captain Krsto Zrnov Popović, fought against the pro-unification forces, Whites.
The royal family was rehabilitated in 2011, by the government and today is headed by Crown Prince Nicholas II who has his own foundation.
Kingdom of Yugoslavia
In 1922 Montenegro formally became the "Oblast of Cettinje" of the Zeta Area in the Kingdom of Serbs, Croats, and Slovenes, annexing for the first time the coastal areas that were former Albania Veneta. In a successive restructuring, in 1929 it became a part of a larger Zeta Banate of the Kingdom of Yugoslavia that reached the Neretva river.
Nicholas's grandson, the Serb King Alexander I dominated the Yugoslav government. Zeta Banovina was one of nine bannovinas which formed the Kingdom and was named after the Serbian Medieval Principality Zeta. It consisted of the present-day Montenegro and parts of Serbia,
