The First Balkan War was a significant conflict that occurred from 1912 until 1913. It took place in the Balkan Peninsula, which is a region in southeastern Europe. The First Balkan War involved a series of battles between the Balkan League (Bulgaria, Greece, Montenegro and Serbia) and the Ottoman Empire, which was located in the Middle East, on the edge of the European continent. Due to the timeframe in which it occurred, the First Balkan War (along with the later Second Balkan War) is considered to be important to World War I. In fact, historians consider the events of both Balkan Wars to be important causes of World War I, which began in 1914 following the assassination of Austrian Archduke Franz Ferdinand.​
FactsthatCrunchImperialism is the practice of a stronger country extending its power over weaker territories by taking political control, using military force, or imposing economic domination. The controlling country uses the territory's land, resources, and people to benefit itself. Before World War I, European powers competed to build empires across Africa, Asia, and the Middle East, which created rivalry and tension between nations.
"When Britain governed India and controlled its trade, that was imperialism in action."
What Caused the First Balkan War?
The 19th century was a period of continuous change and competition in Europe. Not only was it the height of European imperialism, but it also saw the rise of nationalism, which swept across the continent. For instance, Italy formally unified as a country in 1861, and Germany did the same in 1871. In both cases, smaller kingdoms unified into one larger country and saw the people of each country identify with each other nationalistically. This wave of nationalismA strong pride in one’s country or ethnic group, often driving people to seek independence or unification. also swept across the Balkans.​
For centuries, much of the Balkans was ruled by the Ottoman Empire. The Ottoman Empire dated back to around the year 1300 and at its height stretched across the Middle East, Northern Africa, and large sections of Europe. It was a Sunni Islamic state that was based mainly out of modern-day Turkey. For example, the capital of the Ottoman Empire was the city of Constantinople, which today is called Istanbul. While the Ottoman Empire ruled over the Balkans for centuries, by the early 20th century, it was beginning to lose power over the region. This became most evident in 1908 when Austria exerted its influence in the Balkans with the Bosnian Crisis of 1908.​
The Bosnian Crisis began in October of 1908 with the Austrian annexationWhen one country takes control of another territory and adds it to its own land. of Bosnia and Herzegovina. This means that Austria took control over the two territories. Previously they had belonged to the Ottoman Empire, although Austria-Hungary had occupied and run them since 1878, and by this time the Ottoman Empire was in decline and losing its authority in the region. In fact, at the same time, the Balkan state of Bulgaria declared its independence from the Ottoman Empire. Austria’s annexation of Bosnia and Herzegovina created a crisis not only with the leadership of the Ottoman Empire, but also with other surrounding European nations including Italy, Russia and Serbia. This set the stage for the events of the First Balkan War in 1912.​
Major Events of the First Balkan War
At its core, the First Balkan War centered on the conflict between the nations of the Balkans and the Ottoman Empire. As stated previously, the growth of nationalism in Europe led to this conflict, as it pushed nations in the Balkans to fight for their independence. For instance, in the first years of the 20th century, Serbia was hoping to expand throughout the Balkans. After Austria annexed Bosnia and Herzegovina during the Bosnian Crisis of 1908, Serbia focused its attention on the Ottoman Empire. Furthermore, Serbia sought an allianceA formal agreement between countries to support and cooperate with each other, especially in war. in order to assist in its attack against the Ottoman Empire, which led to the formation of the Balkan League.​
The Balkan League was an alliance between several Balkan nations, including: Bulgaria, Greece, Montenegro, and Serbia. Serbia took the first steps in the creation of the alliance when they agreed to an alliance with Bulgaria in 1912. Next, Serbia signed another alliance with its neighboring country, Montenegro. Finally, Bulgaria agreed to an alliance with Greece, and the formation of the Balkan League was complete. Together, the four Balkan nations fought against the Ottoman Empire during the First Balkan War. The war began in October of 1912, when the Balkan League nations declared war against the Ottoman Empire.​
When war began in 1912, each of the nations involved had different levels of military resources and soldiers. Bulgaria was the strongest member nation of the Balkan League and mobilizedWhen a country calls up and organizes its military forces, making them ready for war. over 450,000 soldiers in the First Balkan War. Not only did it have a large number of forces, but the Bulgarian Army was also well organized and equipped, especially in relation to the other nations involved. For their part, Serbia entered the war with over 230,000 soldiers. Greece and Montenegro had considerably fewer forces, with Greece mobilizing approximately 125,000 and Montenegro mobilizing 45,000. Despite their lessened military force, they were both significant factors in the First Balkan War. For example, Greece had a strong naval force that was useful for preventing the Ottoman Empire from shipping in more troops from its empire in the Middle East.
The Ottoman Empire, which faced off against the Balkan League alone, had approximately 436,000 soldiers at the start of the war and added more as the war progressed. However, at this point in history the Ottoman Empire was essentially in decline as a political and militaristic force. For instance, during the First Balkan War, the leadership of the Ottoman Empire struggled to resupply and reinforce their forces in the Balkans. As such, the First Balkan War was a disaster for the Ottoman Empire and resulted in a major loss of territory for them in Europe.
The Ottoman Empire struggled in the First Balkan War due to several factors. First, the border of the Ottoman Empire in the Balkans was large. As such, the Ottomans were not able to properly fortifyTo strengthen a position or border with troops or defenses to protect against attack. and defend it. Instead, the Ottoman Army was spread thin across the border, which allowed the forces of the Balkan League to easily overwhelm them. For instance, Bulgaria easily outnumbered the Ottoman forces in significant battles that included: the Battle of Kirk Kilisse, the Battle of Lule Burgas, the Battle of Adrianople and the First Battle of Çatalca.
The second reason for the failure of the Ottoman Empire in the First Balkan War was the role of Greece in the Aegean Sea. The Greek Navy was well prepared for the war and used their extensive forces in the Aegean Sea to prevent the Ottoman Empire from transporting supplies or soldiers to the Balkans. This was significant as it helped the Balkan League maintain their military advantage during the First Balkan War.​
The third reason for the struggles of the Ottoman Empire was the lack of a reliable transportation network throughout the empire. The Ottoman Empire was quite large and stretched throughout sections of the Middle East and Northern Africa. As such, they had a large population from which they should have been able to call up more soldiers for the First Balkan War. However, the Ottoman Empire lacked the large railroad networks that were common in Europe and therefore did not have the ability to transport troops to the Balkans quickly. This provided the Balkan League with a decisiveHaving a major effect on the outcome of something, in this case a military conflict. advantage. The First Balkan War finally ended on May 30th of 1913 with the signing of the Treaty of London.
Outcomes of the First Balkan War
Historians consider the First Balkan War to be significant for several reasons. First, as a result of its defeat, the Ottoman Empire gave up large sections of territory in the Balkans, which was taken over by the member nations of the Balkan League. Second, the events of the First Balkan War set the stage for the Second Balkan War, which began on June 29th, 1913. Third, historians consider the First Balkan War (and the Second Balkan War) to be significant causes of World War I, which began in 1914.
In fact, the event that sparked World War I was the assassination of the Austrian Archduke Franz Ferdinand on June 28th, 1914. Austria blamed Serbia for this action, since Ferdinand was murdered by Gavrilo Princip – a Bosnian Serb nationalist who had been armed and trained by the Black Hand. The Black Hand was a secret organization aimed at promoting Serbian (and Slavic) nationalism, and helped plan the assassination of Ferdinand in protest of Austria’s influence in the Balkans. As such, this displays that World War I was a direct result of the Bosnian Crisis of 1908 and the two Balkan Wars.
FactsthatCrunchHow did the Balkan Wars of 1912 to 1913 increase tension between Austria-Hungary and Serbia before World War I?
World War I timeline · 1914 – 1918
Key Vocabulary
Imperialism
Nationalism
Annexation
Alliance
Mobilized
Fortify
Decisive
Frequently Asked Questions
When did the First Balkan War take place?
The First Balkan War lasted from October of 1912 until May of 1913. It ended with the signing of the Treaty of London on May 30th, 1913. The fighting took place in the Balkan Peninsula, a region in southeastern Europe.
Who fought in the First Balkan War?
The war was fought between the Balkan League and the Ottoman Empire. The Balkan League was an alliance of four nations, which were Bulgaria, Greece, Montenegro, and Serbia. These four countries joined forces to attack the weakening Ottoman Empire in Europe.
What caused the First Balkan War?
The main cause was the rise of nationalism, which pushed Balkan nations to seek independence from Ottoman rule. The Ottoman Empire was also in decline and losing its grip on the region. The Bosnian Crisis of 1908 further weakened Ottoman power and set the stage for war.
Why did the Ottoman Empire lose the First Balkan War?
The Ottoman Empire lost mainly because its long border in the Balkans was hard to defend. Its army was spread thin and easily overwhelmed by the Balkan League. The Greek Navy also blocked supplies and troops from crossing the Aegean Sea, and poor railroads slowed Ottoman reinforcements.
How is the First Balkan War connected to World War I?
Historians view the First Balkan War as one of the important causes of World War I. The conflict raised tensions in the Balkans and led to the Second Balkan War in 1913. These events helped spark the crisis that began the larger war after the assassination of Archduke Franz Ferdinand in 1914.
Cite This Article
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MLA: Beck, Elias. “First Balkan War: A Detailed Summary.” HistoryCrunch, 28 September 2026, https://historycrunch.com/first-balkan-war/.
APA: Beck, E. (2026). First Balkan War: A Detailed Summary. HistoryCrunch. https://historycrunch.com/first-balkan-war/
Chicago: Beck, Elias. “First Balkan War: A Detailed Summary.” HistoryCrunch. September 28, 2026. https://historycrunch.com/first-balkan-war/
Sources
- Hew Strachan, The First World War.
- John Keegan, The First World War.
- Imperial War Museum
