The Balkans theatre or Balkan campaign was a theatre of
World War I
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
fought between the
Central Powers
The Central Powers, also known as the Central Empires,; ; , ; were one of the two main coalitions that fought in World War I (1914–1918). It consisted of the German Empire, Austria-Hungary, the Ottoman Empire, and the Kingdom of Bulga ...
(
Austria-Hungary
Austria-Hungary, also referred to as the Austro-Hungarian Empire, the Dual Monarchy or the Habsburg Monarchy, was a multi-national constitutional monarchy in Central Europe#Before World War I, Central Europe between 1867 and 1918. A military ...
,
Bulgaria
Bulgaria, officially the Republic of Bulgaria, is a country in Southeast Europe. It is situated on the eastern portion of the Balkans directly south of the Danube river and west of the Black Sea. Bulgaria is bordered by Greece and Turkey t ...
,
Germany
Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
and the
Ottoman Empire
The Ottoman Empire (), also called the Turkish Empire, was an empire, imperial realm that controlled much of Southeast Europe, West Asia, and North Africa from the 14th to early 20th centuries; it also controlled parts of southeastern Centr ...
) and the
Allies (
Serbia
, image_flag = Flag of Serbia.svg
, national_motto =
, image_coat = Coat of arms of Serbia.svg
, national_anthem = ()
, image_map =
, map_caption = Location of Serbia (gree ...
,
Montenegro
, image_flag = Flag of Montenegro.svg
, image_coat = Coat of arms of Montenegro.svg
, coa_size = 80
, national_motto =
, national_anthem = ()
, image_map = Europe-Mont ...
,
France
France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...
, the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...
,
Russia
Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
,
Italy
Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...
, and later,
Greece
Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to th ...
).
The offensive began in 1914 with three failed Austro-Hungarian
offensives into Serbia. A new attempt a year later by the combined forces of Austria-Hungary, Germany, and Bulgaria led to the
conquest and occupation of Serbia and
Montenegro
, image_flag = Flag of Montenegro.svg
, image_coat = Coat of arms of Montenegro.svg
, coa_size = 80
, national_motto =
, national_anthem = ()
, image_map = Europe-Mont ...
. The Serbian military did not surrender,
retreating through the mountains of Albania and evacuated to
Corfu
Corfu ( , ) or Kerkyra (, ) is a Greece, Greek island in the Ionian Sea, of the Ionian Islands; including its Greek islands, small satellite islands, it forms the margin of Greece's northwestern frontier. The island is part of the Corfu (regio ...
before reforming in
Salonika
Thessaloniki (; ), also known as Thessalonica (), Saloniki, Salonika, or Salonica (), is the second-largest city in Greece (with slightly over one million inhabitants in its Thessaloniki metropolitan area, metropolitan area) and the capital cit ...
a few months later. On the
Macedonian front, the
Royal Serbian Army joined the Franco-British
Allied Army of the Orient and fought a protracted
trench war against Bulgarian and German forces. The Allied army presence in Greece resulted in the
National Schism on whether Greece should join the
Allies or remain neutral, which would benefit the Central Powers. Greece eventually joined the Allied Powers in 1917. In September 1918, the
Vardar Offensive
The Vardar offensive () was a World War I military operation, fought between 15 and 29 September 1918. The operation took place during the final stage of the Balkans Campaign (World War I), Balkans Campaign. On 15 September, a combined Allied A ...
had broken through the Bulgarian lines,
forcing them to surrender.
Serbia, Albania and Montenegro's liberation soon followed.
Overview
The prime cause of the war was hostility between Serbia and Austria-Hungary. Serbia held out against Austria-Hungary for over a year before being defeated in late 1915 during the
Serbian campaign.
Dalmatia
Dalmatia (; ; ) is a historical region located in modern-day Croatia and Montenegro, on the eastern shore of the Adriatic Sea. Through time it formed part of several historical states, most notably the Roman Empire, the Kingdom of Croatia (925 ...
was a strategic region during the war that Italy and Serbia intended to seize from Austria-Hungary. Italy entered the war upon agreeing to the
1915 Treaty of London, which promised them a substantial portion of the territory. However, the nation was granted only a small part of Dalmatia in the
1919 Treaty of Versailles, leading to discontent among the Italian populace. This resentment, coupled with a desire to restore national pride, provided fertile ground for the emergence of
fascist
Fascism ( ) is a far-right, authoritarian, and ultranationalist political ideology and movement. It is characterized by a dictatorial leader, centralized autocracy, militarism, forcible suppression of opposition, belief in a natural soci ...
ideology under the leadership of
Benito Mussolini
Benito Amilcare Andrea Mussolini (29 July 188328 April 1945) was an Italian politician and journalist who, upon assuming office as Prime Minister of Italy, Prime Minister, became the dictator of Fascist Italy from the March on Rome in 1922 un ...
. Mussolini's promise to rejuvenate Italy and return it to a position of power resonated with many Italians contributing to the rise of his "
Fasces of Combat" in the country.
During World War I, the retreating Serbian troops fled to Albania, prompting the Central Powers to invade Albania. To aid the Serbian forces, Italian transport ships in the Adriatic Sea helped evacuate them to
Corfu
Corfu ( , ) or Kerkyra (, ) is a Greece, Greek island in the Ionian Sea, of the Ionian Islands; including its Greek islands, small satellite islands, it forms the margin of Greece's northwestern frontier. The island is part of the Corfu (regio ...
and other Greek islands before being relocated to
Thessaloniki
Thessaloniki (; ), also known as Thessalonica (), Saloniki, Salonika, or Salonica (), is the second-largest city in Greece (with slightly over one million inhabitants in its Thessaloniki metropolitan area, metropolitan area) and the capital cit ...
. Meanwhile, the Allies landed in neutral Greece and formed the
Macedonian front. In 1917, Greece joined the war on the Allies side, and the multinational
Allied Army of the Orient, stationed in northern Greece, launched an offensive in 1918. The offensive resulted in Bulgaria seeking a peace treaty, the recapture of Serbia, and a halt only at the border of Hungary in November 1918.
Serbian–Montenegrin campaign
The Serbian forces defended against the larger
Austro-Hungarian Army
The Austro-Hungarian Army, also known as the Imperial and Royal Army,; was the principal ground force of Austria-Hungary from 1867 to 1918. It consisted of three organisations: the Common Army (, recruited from all parts of Austria-Hungary), ...
due to a Russian invasion from the north. In 1915, Austria-Hungary placed additional soldiers on the southern front and brought Bulgaria as an ally for the
Central Powers
The Central Powers, also known as the Central Empires,; ; , ; were one of the two main coalitions that fought in World War I (1914–1918). It consisted of the German Empire, Austria-Hungary, the Ottoman Empire, and the Kingdom of Bulga ...
.
Soon, the Serbian military was attacked from the north and the east, forcing a
retreat to Greece. Despite the loss, the retreat was successful, and the Serbian military remained operational in Greece with a newly-established base.
Italian campaign

Before direct intervention in the war,
Italy
Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...
had occupied the port of
Vlorë
Vlorë ( ; ; sq-definite, Vlora) is the List of cities and towns in Albania, third most populous city of Albania and seat of Vlorë County and Vlorë Municipality. Located in southwestern Albania, Vlorë sprawls on the Bay of Vlorë and is surr ...
in Albania in December 1914.
[Nigel Thomas. Armies in the Balkans 1914-18. Osprey Publishing, 2001. Pp. 17.] Upon entering the war, Italy spread its occupation to the region of southern
Albania
Albania ( ; or ), officially the Republic of Albania (), is a country in Southeast Europe. It is located in the Balkans, on the Adriatic Sea, Adriatic and Ionian Seas within the Mediterranean Sea, and shares land borders with Montenegro to ...
beginning in the Autumn of 1916.
Italian forces in 1916 recruited Albanian irregulars to serve alongside them.
Italy, with the permission of Allied command, occupied
Northern Epirus
Northern Epirus (, ; ) is a term used for specific parts of southern Albania which were first claimed by the Kingdom of Greece in the Balkan Wars and later were associated with the Greek minority in Albania and Greece-Albania diplomatic relation ...
on August 23, 1916, forcing the Greek military to withdraw its occupation forces in the area.
In June 1917, Italy proclaimed central and southern Albania to be a protectorate of Italy. Northern Albania was allocated to the states of Serbia and Montenegro.
By October 31, 1918, French and Italian forces had expelled the Austro-Hungarian military from Albania.
Dalmatia
Dalmatia (; ; ) is a historical region located in modern-day Croatia and Montenegro, on the eastern shore of the Adriatic Sea. Through time it formed part of several historical states, most notably the Roman Empire, the Kingdom of Croatia (925 ...
was a strategic region during
World War I
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
that Italy and Serbia intended to seize from Austria-Hungary. Italy joined the
Allies in 1915 upon agreeing to the
London Pact, which guaranteed it the right to annex a large portion of Dalmatia in exchange for Italy's participation on the Allied side. From November 5 to 6, 1918, Italian forces were reported to have reached
Lissa,
Lagosta,
Sebenico, and other localities on the Dalmatian coast.
By the end of hostilities in November 1918, the Italian military had seized control of the entire portion of Dalmatia that had been guaranteed to Italy by the London Pact and by the 17th had captured Fiume as well.
[Paul O'Brien. ''Mussolini in the First World War: the Journalist, the Soldier, the Fascist''. Oxford, England, UK; New York, New York, US: Berg, 2005. Pp. 17.] In 1918, Admiral
Enrico Millo declared himself Italy's Governor of Dalmatia.
The famous nationalist
Gabriele d'Annunzio supported the seizure of Dalmatia and proceeded to Zadar in an Italian warship in December 1918.
Bulgaria

In the aftermath of the
Balkan Wars
The Balkan Wars were two conflicts that took place in the Balkans, Balkan states in 1912 and 1913. In the First Balkan War, the four Balkan states of Kingdom of Greece (Glücksburg), Greece, Kingdom of Serbia, Serbia, Kingdom of Montenegro, M ...
, Bulgarian opinion turned against Russia and the Western powers, whom the Bulgarians felt had done nothing to help them. Russia blamed Bulgaria for breaking up the alliance it had forged and for starting the
Second Balkan War
The Second Balkan War was a conflict that broke out when Kingdom of Bulgaria, Bulgaria, dissatisfied with its share of the spoils of the First Balkan War, attacked its former allies, Kingdom of Serbia, Serbia and Kingdom of Greece, Greece, on 1 ...
against its former allies and now looked to Serbia as a more reliable Slavic ally against Austria-Hungary. The Bulgarian government aligned itself with Germany and Austria-Hungary, even though this meant also becoming an ally of the
Ottomans
Ottoman may refer to:
* Osman I, historically known in English as "Ottoman I", founder of the Ottoman Empire
* Osman II, historically known in English as "Ottoman II"
* Ottoman Empire
The Ottoman Empire (), also called the Turkish Empir ...
, Bulgaria's traditional enemy. Bulgaria could no longer hold claims against the Ottomans, but Serbia, Greece, and Romania (allies of Britain and France) still held lands the Bulgarians perceived as Bulgarian.
Bulgaria, recuperating from the Balkan Wars, sat out the first year of World War I. When Germany promised Bulgaria all of
Serbian Macedonia, parts of northeastern Serbia, as well as a new loan of 200,000,000
gold francs, Bulgaria declared war on Serbia in October 1915. Britain, France and Italy then declared war on Bulgaria.
Although Bulgaria, allied with Germany and Austria-Hungary, won military victories against Serbia and Romania: occupying much of Southern Serbia (taking
Nish, Serbia's war capital on November 5), advancing into
Greek Macedonia. They were assisted by the
IMRO
The Internal Macedonian Revolutionary Organization (IMRO; ; ), was a secret revolutionary society founded in the Ottoman territories in Europe, that operated in the late 19th and early 20th centuries.
Founded in 1893 in Salonica, it init ...
who joined the Bulgarian army as the
11th Macedonian Infantry Division. Bulgaria later took
Dobruja
Dobruja or Dobrudja (; or ''Dobrudža''; , or ; ; Dobrujan Tatar: ''Tomrîğa''; Ukrainian language, Ukrainian and ) is a Geography, geographical and historical region in Southeastern Europe that has been divided since the 19th century betw ...
from the Romanians in September 1916, the war soon became unpopular with the majority of Bulgarian people, who had suffered enormous economic hardship. The
Russian Revolution of February 1917 had a significant effect in Bulgaria, spreading
antiwar
An anti-war movement is a social movement in opposition to one or more nations' decision to start or carry on an armed conflict. The term ''anti-war'' can also refer to pacifism, which is the opposition to all use of military force during co ...
and
anti-monarchist sentiment among the troops and in the cities.
In September 1918, a collective group of Serbian and Allied forces broke through on the
Macedonian front in the
Vardar Offensive
The Vardar offensive () was a World War I military operation, fought between 15 and 29 September 1918. The operation took place during the final stage of the Balkans Campaign (World War I), Balkans Campaign. On 15 September, a combined Allied A ...
. While Bulgarian forces
stopped them in
Dojran,
Tsar Ferdinand was forced to sue for peace.
To head off the revolutionaries,
Ferdinand
Ferdinand is a Germanic name composed of the elements "journey, travel", Proto-Germanic , abstract noun from root "to fare, travel" (PIE , "to lead, pass over"), and "courage" or "ready, prepared" related to Old High German "to risk, ventu ...
abdicated in favour of his son
Boris III. The revolutionaries were suppressed successfully, and their forces disbanded. Under the
Treaty of Neuilly (November 1919), Bulgaria lost its Aegean coastline in favour of the Principal Allied and Associated Powers (transferred later by them to Greece) and nearly all of its Macedonian territory to the new state of
Yugoslavia
, common_name = Yugoslavia
, life_span = 1918–19921941–1945: World War II in Yugoslavia#Axis invasion and dismemberment of Yugoslavia, Axis occupation
, p1 = Kingdom of SerbiaSerbia
, flag_p ...
, and had to give Dobruja back to the Romanians (see also Dobruja, Western Outlands, Western Thrace).
National Schism
Following the start of
World War I
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
the
Kingdom of Greece
The Kingdom of Greece (, Romanization, romanized: ''VasÃleion tis Elládos'', pronounced ) was the Greece, Greek Nation state, nation-state established in 1832 and was the successor state to the First Hellenic Republic. It was internationally ...
was politically split between joining the war and being neutral, led by the Pro-Entente
Venizelos and the pro-Central Powers
King Constantine. Following the
conquest of Serbia Venizelos allowed the Allies into
Thessaloniki
Thessaloniki (; ), also known as Thessalonica (), Saloniki, Salonika, or Salonica (), is the second-largest city in Greece (with slightly over one million inhabitants in its Thessaloniki metropolitan area, metropolitan area) and the capital cit ...
leading to the creation of the
Macedonian front. Following this
Venizelos set up the
Provisional Government of National Defence in Allied-controlled North Greece.
The Allies and the Provisional Government of National Defence clashed during the
Noemvriana.
The inability of the
Kingdom of Greece
The Kingdom of Greece (, Romanization, romanized: ''VasÃleion tis Elládos'', pronounced ) was the Greece, Greek Nation state, nation-state established in 1832 and was the successor state to the First Hellenic Republic. It was internationally ...
to join
World War I
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
against the
Central Powers
The Central Powers, also known as the Central Empires,; ; , ; were one of the two main coalitions that fought in World War I (1914–1918). It consisted of the German Empire, Austria-Hungary, the Ottoman Empire, and the Kingdom of Bulga ...
lead the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...
and
France
France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...
to recognize the
Provisional Government of National Defence as the legitimate government of
Greece
Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to th ...
, and blockaded Greece. In June, 1917 the
French captured Thessaly and
King Constantine fled Greece and
Venizelos re-entered Athens, declaring war on the
Central Powers
The Central Powers, also known as the Central Empires,; ; , ; were one of the two main coalitions that fought in World War I (1914–1918). It consisted of the German Empire, Austria-Hungary, the Ottoman Empire, and the Kingdom of Bulga ...
in July.
Macedonian Front
In 1915, the Austro-Hungarians gained the support of Germany and allied with Bulgaria. Serbian forces were attacked from both north and south, forcing them to retreat through Montenegro and Albania, with only 155,000 Serbs, mainly soldiers, reaching the coast of the
Adriatic Sea
The Adriatic Sea () is a body of water separating the Italian Peninsula from the Balkans, Balkan Peninsula. The Adriatic is the northernmost arm of the Mediterranean Sea, extending from the Strait of Otranto (where it connects to the Ionian Se ...
and evacuating to Greece by Allied ships.
The
Macedonian front stabilized roughly around the Greek border after the intervention of a Franco-British-Italian force that had landed in
Salonica. The German generals had not let the Bulgarian army advance toward Salonica because they hoped to persuade the Greeks to join the Central Powers.
In 1918, after a prolonged build-up, the Allies, under French General
Franchet d'Esperey, led a combined French, Serbian, Greek and British army
attack out of Greece. His initial victories convinced the Bulgarian government to sue for peace. He then attacked the north and defeated the German and Austro-Hungarian forces that tried to halt his offensive.
By October 1918, having
recaptured all of Serbia his forces prepared to invade Hungary proper until the Hungarian leadership offered to surrender in November 1918, halting the offensive.
Results
The French and British each kept six divisions on the Greek frontier from 1916 to late 1918. The French and British went to Greece to help Serbia, but with Serbia's conquest in the fall of 1915, their continued presence there did not have an effect, so they relocated their forces to the Western Front.
In mid-1918, led by General Franchet d'Esperey, those forces were added to in order to conduct a major offensive on the south flank of the Central Powers (8 French divisions, 6 British divisions, 1 Italian division, 12 Serbian divisions).
[Bernard Schnetzler,'' Les erreurs stratégiques pendant la Première Guerre Mondiale'', Economica, 2011 ] After the successful offensive launched on September 10, 1918, they freed Belgrade, forcing Bulgaria to an armistice on September 29, threatening Austria-Hungary (which accepted an armistice on November 4, 1918) and the German political leadership.
The historian
John Keegan
Sir John Desmond Patrick Keegan (15 May 1934 – 2 August 2012) was an English military historian, lecturer, author and journalist. He wrote many published works on the nature of combat between prehistory and the 21st century, covering land, ...
argued that "the installation of a violently nationalist and anti-Turkish government in Athens led to Greek mobilization in the cause of the
"Great Idea" - the recovery of the Greek Empire in the east - which would complicate the Allied effort to resettle the peace of Europe for years after the war ended."
References
Sources
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External links
{{Authority control
Wars involving the Balkans
Campaigns and theatres of World War I
European theatre of World War I
Albania in World War I
Military operations of World War I involving Austria-Hungary
Bulgaria in World War I
Greece in World War I
Serbia in World War I
Military operations of World War I involving Germany
Military operations of World War I involving the Ottoman Empire
.
Modern history of the Balkans