Serbia

Serbia is an Balkan country involved in World War 1. The country lasted until 1915 when Bulgaria joined the war. An French treaty with Bulgaria made the country

reformed, which it did an campaign that helped the allied war effort.

History
In the course of the First Balkan War in 1912, the Balkan League defeated the Ottoman Empire and captured its European territories, which enabled territorial expansion of the Kingdom of Serbia into regions of Raška, Kosovo, Metohija, and Vardarian Macedonia. The Second Balkan War soon ensued when Bulgaria turned on its former allies, but was defeated, resulting in the Treaty of Bucharest. In two years, Serbia enlarged its territory and its population by 50%,[citation needed] it also suffered high casualties on the eve of World War I, with more than 36,000 dead. Austria-Hungary became wary of the rising regional power on its borders and its potential to become an anchor for unification of Serbs and other South Slavs, and the relationship between the two countries became tense.

The assassination of Archduke Franz Ferdinand of Austria on 28 June 1914 in Sarajevo by Gavrilo Princip, a member of the Young Bosnia organisation, led to Austria-Hungary declaring war on Serbia, on 28 July. Local war escalated when Germany declared war on Russia and invaded France and Belgium, thus drawing Great Britain into the conflict that became the First World War. Serbia won the first major battles of World War I, including the Battle of Cer, and the Battle of Kolubara, marking the first Allied victories against the Central Powers in World War I.

Despite initial success, it was eventually overpowered by the Central Powers in 1915 and Austro-Hungarian occupation of Serbia followed. Most of its army and some people retreated through Albania to Greece and Corfu, suffering immense losses on the way. Serbia was occupied by the Central Powers. After the Central Powers military situation on other fronts worsened, the remains of the Serb army returned east and led a final breakthrough through enemy lines on 15 September 1918, liberating Serbia and defeating Bulgaria and Austria-Hungary. Serbia, with its campaign, was a major Balkan Entente Power which contributed significantly to the Allied victory in the Balkans in November 1918, especially by helping France force Bulgaria's capitulation.

Serbia's casualties accounted for 8% of the total Entente military deaths; 58% (243,600) soldiers of the Serbian army perished in the war. The total number of casualties is placed around 700,000, more than 16% of Serbia's prewar size, and a majority (57%) of its overall male population. Serbia suffered the biggest casualty rate in World War I.

As the Austro-Hungarian Empire collapsed, the territory of Syrmia united with Serbia on 24 November 1918.[citation needed] Just a day later on 25 November 1918 Grand National Assembly of Serbs, Bunjevci and other Slavs in Banat, Bačka and Baranja declared the unification of Banat, Bačka, and Baranja to the Kingdom of Serbia.