Greece Invades Bulgaria

A frontier incident between Greece and Bulgaria resulted in a brief invasion of southwestern Bulgaria by Greece. The League of Nations intervened to resolve the conflict.

Summary of Event

In October of 1925, a violent but minor frontier incident between Bulgaria and Greece caused the Greek government to respond with a medium-sized military action against Bulgaria. The Bulgarian government in Sofia appealed to the League of Nations League of Nations;Greco-Bulgarian conflict[Grecobulgarian conflict] for support in the conflict, and the League engineered a cease-fire, conducted an investigation, and had issued its findings by December of 1925. The lion’s share of blame for the violations of sovereignty, deaths, and material destruction belonged to Greece, which was then forced to pay a hefty fine. [kw]Greece Invades Bulgaria (Oct. 23, 1925)
[kw]Invades Bulgaria, Greece (Oct. 23, 1925)
[kw]Bulgaria, Greece Invades (Oct. 23, 1925)
Greece, invasion of Bulgaria
Bulgaria;Greek invasion
[g]Balkans;Oct. 23, 1925: Greece Invades Bulgaria[06540]
[g]Bulgaria;Oct. 23, 1925: Greece Invades Bulgaria[06540]
[g]Greece;Oct. 23, 1925: Greece Invades Bulgaria[06540]
[c]Diplomacy and international relations;Oct. 23, 1925: Greece Invades Bulgaria[06540]
[c]Wars, uprisings, and civil unrest;Oct. 23, 1925: Greece Invades Bulgaria[06540]
Briand, Aristide
Pangalos, Theodoros

The roots of this conflict lay in the tangled domestic political situations in both Greece and Bulgaria. To some degree, however, the incidents also reflected the unresolved national question that had plagued Greco-Bulgarian relations for more than a decade. The cause of the conflict was not, it should be noted, related to any of the so-called ancient ethnic hatreds between the Balkan peoples.

In the period 1912-1913, a Balkan League—consisting of Montenegro, Bulgaria, Serbia, and Greece—had, with Russian backing, overrun most of the Ottoman Empire’s remaining (and ethnically diverse) territories in Europe. This First Balkan War Balkan Wars (1912-1913) (October, 1912-May, 1913), was a forerunner of World War I, which began in 1914; it was also a cruel variety of intra-European imperialism, practiced not by the major world powers like Britain and France overseas but closer to home, by four states that claimed to be “liberating” their own historical or ethnic territories. The feeding frenzy among the four brought them into conflict with each other and with the diverse populations they now ruled. The Second Balkan War (1913) ensued, and in it Bulgaria was humiliated by a number of states whose leaders thought Bulgaria had seized an unacceptable amount of land in Macedonia and Thrace.

A final key element behind the Greek invasion of Bulgaria was the revolutionary nationalist organization known as the Internal Macedonian Revolutionary Organization Internal Macedonian Revolutionary Organization (IMRO), which had originally been founded in the 1890’s and then split into several factions. The Mihailovists, an IMRO fraction, wanted to annex the large region of Macedonia bordering Bulgaria. In 1925, both Serbia (which became part of Yugoslavia in 1918) and Greece held large portions of Macedonia, so their governments and populations were targeted by IMRO operatives. The Bulgarian government was unable to dismantle the terrorist group, much to the anger of its neighbors. Meanwhile, in Greece, nationalist sentiments were also running high, and the irresponsible military leader, General Theodoros Pangalos, was presented with a tempting opportunity to both mobilize the public and satisfy his urge for personal glory. The area around the southern Bulgarian border town of Petric became a center of operations for the Mihailovists’ aims within Bulgaria. They also used Petric as a base from which to launch attacks into the disputed border areas of nearby Greece and Yugoslavia. Several such forays into Greece had already been made.

It was in the exceedingly tense atmosphere of this cross-border terrorism—which Athens accused Sofia of being unwilling to stop—that the frontier incident that triggered the invasion occurred between Greek and Bulgarian troops. On October 19, 1925, the Bulgarian border forces killed one Greek officer and one soldier near Demir Hissár, and Greek outrage was immediate and thunderous, particularly because some Greeks had also recently been killed in Bulgaria. Bulgaria’s neighbors also feared that the komitadjis, as the Bulgarian underground fighters were called, were being supported by the Soviet Union in order to advance a communist agenda.

The ensuing conflict became front-page news around the world. Before resorting to military means, the Greeks first demanded satisfaction within forty-eight hours in the form of an indemnity of two million gold francs (more than eighty thousand dollars), an official apology, and the punishment of the responsible Bulgarian parties. When these demands were not met, more than a thousand Greek troops, accompanied by air and artillery units, crossed the border and moved toward the city of Petric. The incursion began on October 23, and Bulgaria contacted the League of Nations in Geneva on the same day. Led by the French foreign minister Aristide Briand, the League Council, a subgroup of both permanent and nonpermanent members, agreed to meet on October 26 to consider the issue. The League quickly demanded that the two countries agree to accept its decision and that the fighting cease and troops returned to their respective territories before any adjudication would take place, and Greece and Bulgaria agreed to these conditions.

Over a period of two days, the Greeks advanced about eight kilometers inside Bulgaria along a front that was roughly thirty kilometers wide. A number of Bulgarian homes and fields were destroyed or plundered, and refugees fled. Some accounts give the number of Bulgarian soldiers and civilians killed as fifty, and many others were wounded. Greek casualty figures are not available, but Bulgarian resistance had stiffened as the invaders approached Petric, and there were reports of Bulgarian sniper activity.

When the Greeks heard of President Briand’s demand, attacks ceased, and Greek troops quickly withdrew. The League first sent the military attachés from nearby British, French, and Italian legations to conduct a preliminary report, which was followed by a commission of inquiry. This special commission presented its findings in a report on December 3, 1925. It found that Bulgaria had been at fault for the original incident, but that Greece’s culpability in using aggression instead of the good offices of the League was much greater; the penalty to be paid by Greece, adjusted downward for the indemnity owed by Bulgaria, was set at £45,000, or about $219,000. Greece paid the sanction in February of 1926. Bulgaria had based its appeal for the League to safeguard the peace on Article 11 of the Covenant, the constitution-like founding document of the League’s principles and procedures. The League considered economic sanctions or a military show of force under Article 16, but these were not necessary.

Bulgaria was predisposed to rely on the League to help resolve this dispute because of a number of dealings that already linked Sofia and Geneva. The League had helped raise reconstruction loans for Bulgaria to repair damage from World War I. Bulgaria’s appeal to the League makes sense, then, given its functional relationship with that body as a defeated belligerent attempting to regain international acceptance. Greece’s grudging acceptance of the League’s intervention—penalties imposed on it by its former allies in the recent world war—indicates the momentum of the Locarno Pact of 1925, Locarno Treaties (1925) which prepared a rehabilitated Germany for a new international role, had given the League considerable authority. When the League was not hindered by internal bickering or budget constraints, it could be quite effective.


One of the most important outcomes of the 1925 Greco-Bulgarian conflict was the demonstration of the effectiveness of the League of Nations. Diplomats within the League came to view Article 11 as justification for earlier intervention in nascent conflicts than previously allowed by an emphasis on Article 16, which referred to full-blown cases of war. A second key result was that the importance of irredenta (an area culturally connected to one nation but politically controlled by another) in the Balkans was still important. Elite and popular preoccupation with these “unredeemed lands”—one country’s territory claimed by another on the basis of historical or strategic rights or of current national or ethnic composition—served to skew the domestic political scene of Greece, Bulgaria, and their neighbors. Perceived foreign threats to conationals or to a culture’s place of origin allowed more constructive, concrete agendas to be relegated to the political sidelines.

With the military, intelligence and secret police services, and underground political groups playing key roles in the framing of political discourse, common developmental needs and historical similarities among the Balkan peoples were minimized; similarly, state budgets for education, the health system, industrial investment in nonmilitary branches, and the all-important agricultural industry were kept anemic. In addition, the continued cultivation of these frontier disputes helped make the Balkan states vulnerable to manipulation at the hands of the Nazis and, to a lesser degree, the Italian fascists.

A final effect was pressure from inside Greece for the ouster of General Pangalos, who had initiated the assault on Bulgaria. As one of Greece’s many antimonarchical but decidedly militaristic strongmen of the period 1924-1935, he held power for fourteen months, and his failed foreign policy adventurism helped bring his government’s downfall. This shift in power was an echo of the tumultuous time in which King George II had abdicated after losing the Greek regions of Asia Minor to the new Turkish state in 1923. Greece, invasion of Bulgaria
Bulgaria;Greek invasion

Further Reading

  • Clogg, Richard. A Concise History of Greece. 2d ed. New York: Cambridge University Press, 2002. An excellent concise history of the country that emphasizes the political instability of the interwar years.
  • Crampton, R. J. A Concise History of Bulgaria. New York: Cambridge University Press, 1997. A model of historical scholarship for narrative histories of small countries. Full of salient comparisons of Bulgarian policies and ideas with those of Europe in general.
  • Stavrianos, Leften. The Balkans Since 1453. New York: New York University Press, 2000. The magisterial work on nearly all aspects of Balkan history by touching on its political, diplomatic, intellectual, and economic, and even to some degree military and social histories.
  • Walters, F. P. A History of the League of Nations. New York: Oxford University Press, 1967. A well-documented source for information on and analysis of individual League projects that lays to rest stereotypes about the League’s supposedly universal ineffectiveness. Also contains biographical information on major diplomats and blow-by-blow accounts, based on diplomatic and newspaper sources, of conflicts and developmental problems that garnered the League’s attention.

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