Kingdom of Bulgaria (World War I)

The **Kingdom of Bulgaria** (Bulgarian: Царство България, *Tsarstvo Bǎlgariya*), also referred to as the **Tsardom of Bulgaria** and the **Third Bulgarian Tsardom**, was a constitutional monarchy in Eastern and Southeastern Europe, which was established on 5 October (O.S. 22 September) 1908 when the Bulgarian state was raised from a principality to a kingdom. Ferdinand I was crowned a Tsar at the Declaration of Independence, mainly because of his military plans and for seeking options for unification of all lands in the Balkan region with an ethnic Bulgarian majority (lands that had been seized from Bulgaria and given to the Ottoman Empire in the Treaty of Berlin).

The state was almost constantly at war throughout its existence, lending to its nickname as "the Balkan Prussia". For several years Bulgaria mobilized an army of more than 1 million people from its population of about 5 million and in the next decade (1910–20) it engaged in three wars – the First and Second Balkan Wars, and the First World War. Following the First World War the Bulgarian army was disbanded and forbidden to exist by the Allied powers, and all plans for national unification of the Bulgarian lands failed. Less than two decades later Bulgaria once again went to war for national unification as part of the Second World War, and once again found itself on the losing side, until it switched sides to the Allies in 1944. In 1946, the monarchy was abolished, its final Tsar was sent into exile and the Kingdom was replaced by the  Republic of Bulgaria.

## Involvement in World War I

In the aftermath of the Balkan Wars, Bulgarian opinion turned against Russia and the western powers, whom the Bulgarians felt had done nothing to help them. The government of Vasil Radoslavov aligned Bulgaria with Germany and Austria-Hungary, even though this meant also becoming an ally of the Ottomans, Bulgaria's traditional enemy. But Bulgaria now had no claims against the Ottomans, whereas Serbia, Greece and Romania (allies of the UK and France) were all in possession of lands perceived in Bulgaria as Bulgarian. Bulgaria, recuperating from the Balkan Wars, sat out the first year of World War I, but when Germany promised to restore the boundaries of the Treaty of San Stefano, Bulgaria, which had the largest army in the Balkans, declared war on Serbia in October 1915. The UK, France, Italy and Russia then declared war on Bulgaria.

Bulgaria, in alliance with Germany, Austria-Hungary and the Ottomans, won military victories against Serbia and Romania, taking much of Macedonia (taking Skopje in October), advancing into Greek Macedonia, and taking Dobruja from the Romanians in September 1916. However, the war soon became unpopular with the majority of Bulgarian people, who suffered great economic hardship and also disliked fighting their fellow Orthodox Christians in alliance with the Muslim Ottomans. The Agrarian Party leader, Aleksandur Stamboliyski, was imprisoned for his opposition to the war. The Russian Revolution of February 1917 had a great effect in Bulgaria, spreading antiwar and anti-monarchist sentiment among the troops and in the cities. In June Radoslavov's government resigned. Mutinies broke out in the army, Stamboliyski was released and a republic was proclaimed.