Bulgaria, Greece, Montenegro, and Serbia (the Balkan League) sign an armistice with the Ottoman Empire, temporarily halting the First Balkan War. (The armistice will expire on February 3, 1913, and hostilities will resume.)

The Tsardom of Bulgaria, also known as the Third Bulgarian Tsardom, usually known in English as the Kingdom of Bulgaria, or simply Bulgaria, was a constitutional monarchy in Southeastern Europe, which was established on 5 October [O.S. 22 September] 1908, when the Bulgarian state was raised from a principality to a tsardom.

The Kingdom of Greece was the Greek nation-state established in 1832 and was the successor state to the First Hellenic Republic. It was internationally recognised by the Treaty of Constantinople, where Greece also secured its full independence from the Ottoman Empire after nearly four centuries. It remained a Kingdom until 1924, when the Second Hellenic Republic was proclaimed, and from the Republic's collapse in 1935 to its dissolution by the Regime of the Colonels in 1973. A referendum following the regime's collapse in 1974 confirmed the effective dissolution of the monarchy and the creation of the Third Hellenic Republic. For much of its existence, the Kingdom's main ideological goal was the Megali Idea, which sought to annex lands with predominately Greek populations.

The Kingdom of Montenegro was a monarchy in southeastern Europe, present-day Montenegro, during the tumultuous period of time on the Balkan Peninsula leading up to and during World War I. Officially it was a constitutional monarchy, but absolutist in practice. On 28 November 1918, following the end of World War I, with the Montenegrin government still in exile, the Podgorica Assembly proclaimed unification with the Kingdom of Serbia, which itself was merged into the Kingdom of Serbs, Croats and Slovenes three days later, on 1 December 1918. This unification with Serbia lasted, through various successor states, for almost 88 years, ending in 2006.

The Kingdom of Serbia was a country located in the Balkans which was created when the ruler of the Principality of Serbia, Milan I, was proclaimed king in 1882. Since 1817, the Principality was ruled by the Obrenović dynasty. The Principality, under the suzerainty of the Ottoman Empire, de facto achieved full independence when the very last Ottoman troops left Belgrade in 1867. The Congress of Berlin in 1878 recognized the formal independence of the Principality of Serbia, and in its composition Nišava, Pirot, Toplica and Vranje districts entered the South part of Serbia.