Between 1912 and 1913, Serbia greatly enlarged its territory through engagement in the First and Second Balkan Wars – Sandžak-Raška, Kosovo Vilayet and Vardar Macedonia were annexed.

Despite brutal oppression and retaliation by the Ottoman authorities, the revolutionary leaders, first Karađorđe and then Miloš Obrenović, succeeded in their goal to liberate Serbia after centuries of Turkish rule.

Bulgarians successfully repelled the Serbs after the decisive victory at the Battle of Slivnitsa and advanced into Serbian territory taking Pirot and clearing the way to Niš.

Negotiations between Russia, Serbia and Bulgaria led to the Serbian-Bulgarian Treaty of Alliance of March 1912, which aimed to conquer and to divide the Ottoman held Macedonia.

At the Battle of Kumanovo Serbs defeated the Ottoman army and proceeded to conquer Skopje and the whole of Kosovo vilayet.

[11] On November 29, 1913, the Drač County of the Kingdom of Serbia was established on the part of the territory of Albania taken from the Ottoman Empire during the First Balkan War.

[15] In a report to Rome, Lazër Mjeda, Archbishop of Skopje, estimated that 25,000 Albanians were killed by Serbian forces during and after the conflict.

Assassination of Archduke Franz Ferdinand triggered a chain of international events that embroiled Russia and the major European powers in the conflict.

The 135,000 soldiers of the Serbian Army retreated through Albania and were evacuated to the Greek island of Corfu, and in spring, 1916, they became part of a newly formed Salonika front.

At the end of the war and the collapse of Austria-Hungary, Serbia experienced a loss of 28 percent of its pre-war population[18] and went through radical changes after the liberation, all within days.

The lost war and the Radical Party's total electoral victory were some of the reasons why King Milan I abdicated in 1889.

[22] King Alexander I of Serbia and his unpopular wife Queen Draga were assassinated inside the Royal Palace in Belgrade on the night of 28–29 May 1903.

The traditionally good relations with Austria-Hungary ended, as the new dynasty relied on the support of the Russian Empire and closer cooperation with Kingdom of Bulgaria.

The Bosnian Crisis of 1908–1909 (also referred to as the Annexation crisis) erupted into public view when on October 5, 1908, the Kingdom of Bulgaria declared its complete independence from Ottoman Empire and on October 6, 1908, when Austria-Hungary announced the annexation of Bosnia and Herzegovina, which was populated mainly by South Slavs.

The districts were: Valjevo, Vranje, Kragujevac, Krajina, Kruševac, Morava, Pirot, Podrinje, Podunavlje, Požarevac, Rudnik, Timok, Toplica, Užice and Crna Reka.

In August 1913, 11 new districts were formed in the newly liberated areas: Bitola, Debar, Kavadarci, Novi Pazar, Kumanovo, Pljevlja, Prizren, Priština, Skopje, Tetovo and Štip.

This opened the way for the descendants of Karađorđe (Karageorge), regarded by Serbs throughout the Balkans as the man who threw off the Turkish yoke, to return to the throne.

Morava Valley was in the strategically important terrestrial route that linked Central Europe with Greece and Constantinople.

The convention obliged Serbia to construct the railway line from Belgrade to Vranje and Turkish and Bulgarian borders in three years.

In addition, the obligation to sign commercial contracts was imposed on Serbia, as well as a claim to carry out regulation works in Đerdap.