Kingdom of Yugoslavia in the context of "Central Serbia"

Yugoslavia was a state concept among the South Slavic intelligentsia and later popular masses from the 19th to early 20th centuries that culminated in its realization after the 1918 collapse of Austria-Hungary at the end of World War I and the formation of the Kingdom of Serbs, Croats and Slovenes. However, from as early as 1922 onward, the kingdom was better known colloquially as Yugoslavia (or similar variants); in 1929 the name was made official when the country was formally renamed the "Kingdom of Yugoslavia".

The creation of Yugoslavia has been described as expansionist and irredentist in its approach to foreign policy, and federalist in its approach to politics, with power centralised in the Serb-dominated government. Despite the idea of Yugoslavism having promoted equality among the South Slavic ethnic groups, the new Yugoslav state was ruled by the Serbian Karađorđević dynasty that sought to implement pro-Serb policies throughout the country, leaving minority groups like Croatians and Bosniaks (Bosnian Muslims) not feeling represented in the new government. This led to the formation of opposition parties that became identified with particular ethnic groups within the country. Similarly, the concept of Yugoslavism became associated with the idea of a South Slavic nation dominated by Serbs; and in some instances, forced cultural assimilation policies introduced by the Serb-led Yugoslav government. However, the creation of Yugoslavia remained popular even among non-Serbs, as it was seen as a means of unification for South Slavs to protect themselves against non-Slavic powers such as Fascist Italy.

The Kingdom of Serbia was a country located in the Balkans which was created when the ruler of the Principality of Serbia, Milan I, was proclaimed king in 1882. Since 1817, the Principality was ruled by the Obrenović dynasty (replaced by the Karađorđević dynasty for a short time). The Principality of Serbia, under the suzerainty of the Turkish Empire, de facto achieved full independence when the very last Ottoman troops left Belgrade in 1867. The Congress of Berlin in 1878 recognized the formal independence of the Principality of Serbia, and in its composition Nišava, Pirot, Toplica and Vranje districts entered the South part of Serbia.

In 1882, Serbia was elevated to the status of a kingdom, initially maintaining a foreign policy friendly to Austria-Hungary before turning to the Russian Empire and France following a coup d'état in 1903. Between 1912 and 1913, Serbia greatly enlarged its territory through engagement in the First and Second Balkan Wars – Sandžak-Raška, Kosovo Vilayet and Vardar Macedonia were annexed. At the end of World War I in 1918 it united with Vojvodina and the Kingdom of Montenegro, and in December 1918 it merged with the newly created State of Slovenes, Croats and Serbs to form the Kingdom of Serbs, Croats and Slovenes (later known as Kingdom of Yugoslavia) under the continued rule of the Karađorđević dynasty.

Pirin Macedonia or Bulgarian Macedonia (Bulgarian: Пиринска Македония; Българска Македония) (Pirinska Makedoniya or Bulgarska Makedoniya), which today is in southwestern Bulgaria, is the third-biggest part of the geographical region of Macedonia. This part coincides with the borders of Blagoevgrad Province, as well as the surrounding area of Barakovo from Kyustendil Province. After World War I, Strumica and the surrounding area were broken away from the region and were ceded to Yugoslavia.

It covers an area of about 6,798 km, which is 10.18% of the geographical region of Macedonia. One of the regional centers is Blagoevgrad. The region borders Kyustendil Province and Sofia Province to the north, Pazardzhik Province and Smolyan Province to the east, Greece to the south, and North Macedonia to the west. The population is estimated around 290,000 people.

The Allies, formally referred to as the United Nations from 1942, were an international military coalition formed during World War II (1939–1945) to oppose the Axis powers. Its principal members were the "Big Four" – the United Kingdom, Soviet Union, United States, and China.

Membership in the Allies varied during the course of the war. When the conflict broke out on 1 September 1939, the Allied coalition consisted of the United Kingdom, France, and Poland, as well as their respective dependencies, such as British India. They were joined by the independent dominions of the British Commonwealth: Canada, Australia, New Zealand and South Africa. Consequently, the initial alliance resembled that of the First World War. As Axis forces began invading northern Europe and the Balkans, the Allies added the Netherlands, Belgium, Norway, Greece, and Yugoslavia. The Soviet Union, which initially had a nonaggression pact with Germany and participated in its invasion of Poland, joined the Allies after the German invasion of the Soviet Union in June 1941. The United States, while providing some material support to European Allies since September 1940, remained formally neutral until the Japanese attack on Pearl Harbor in December 1941, after which it declared war and officially joined the Allies. China had already been at war with Japan since 1937, and formally joined the Allies in December 1941.

The Kingdom of Italy was governed by the National Fascist Party from 1922 to 1943 with Benito Mussolini as prime minister transforming the country into a totalitarian dictatorship. The Fascists crushed political opposition, while promoting economic modernization, traditional social values and a rapprochement with the Roman Catholic Church. They also promoted imperialism, resulting in the expansion of the Italian Empire.

According to historian Stanley G. Payne, "[the] Fascist government passed through several relatively distinct phases". The first phase (1922–1925) was nominally a continuation of the parliamentary system, albeit with a "legally-organized executive dictatorship". In foreign policy, Mussolini ordered the pacification of Libya against rebels in the Italian colonies of Tripolitania and Cyrenaica (eventually unified in Italian Libya), inflicted the bombing of Corfu, established a protectorate over Albania, and annexed the city of Fiume into Italy after a treaty with the Kingdom of Yugoslavia. The second phase (1925–1929) was "the construction of the Fascist dictatorship proper". The third phase (1929–1935) saw less interventionism in foreign policy. The fourth phase (1935–1940) was characterized by an aggressive foreign policy: the Second Italo-Ethiopian War, which was launched from Eritrea and Somaliland; confrontations with the League of Nations, leading to sanctions; growing economic autarky; the invasion of Albania; and the signing of the Pact of Steel. The fifth phase (1940–1943) was World War II itself, ending in military defeat, while the sixth and final phase (1943–1945) was the rump Salò Government under German control.

The Tripartite Pact, also known as the Berlin Pact, was an agreement between Germany, Italy, and Japan signed in Berlin on 27 September 1940 by, respectively, Joachim von Ribbentrop, Galeazzo Ciano, and Saburō Kurusu (in that order) and in the presence of Adolf Hitler. It was a defensive military alliance that was eventually joined by Hungary (20 November 1940), Romania (23 November 1940), Slovakia (24 November 1940), Bulgaria (1 March 1941), and Yugoslavia (25 March 1941). Yugoslavia's accession provoked a coup d'état in Belgrade two days later. Germany, Italy, and Hungary responded by invading Yugoslavia. The resulting Italo-German client state, known as the Independent State of Croatia, joined the pact on 15 June 1941.

The Tripartite Pact was, together with the Anti-Comintern Pact and the Pact of Steel, one of a number of agreements between Germany, Japan, Italy, and other countries of the Axis powers governing their relationship.

The Treaty of Lausanne (French: Traité de Lausanne, Turkish: Lozan Antlaşması) is a peace treaty negotiated during the Lausanne Conference of 1922–1923 and signed in the Palais de Rumine in Lausanne, Switzerland, on 24 July 1923. The treaty officially resolved the conflict that had initially arisen between the Ottoman Empire and the Allied French Republic, British Empire, Kingdom of Italy, Empire of Japan, Kingdom of Greece, Kingdom of Serbia, and the Kingdom of Romania since the outset of World War I. The original text of the treaty is in English and French. It emerged as a second attempt at peace after the failed and unratified Treaty of Sèvres, which had sought to partition Ottoman territories. The earlier treaty, signed in 1920, was later rejected by the Turkish National Movement which actively opposed its terms. As a result of Greek defeat in the Greco-Turkish War, Turkish forces recaptured İzmir, and the Armistice of Mudanya was signed in October 1922. This armistice provided for the exchange of Greek-Turkish populations and allowed unrestricted civilian, non-military passage through the Turkish Straits.

Turkey ratified the treaty on 23 August 1923, and all other signatories did so by 16 July 1924. The Treaty of Lausanne became effective on 6 August 1924.

Bosnia and Herzegovina, often referred to as Bosnia-Herzegovina or short as Bosnia, is a country in Southeast Europe. Situated on the Balkan Peninsula, it borders Serbia to the east, Montenegro to the southeast, and Croatia to the north and southwest, with a 20-kilometre-long (12-mile) coast on the Adriatic Sea in the south. Bosnia has a moderate continental climate with hot summers and cold, snowy winters. Its geography is largely mountainous, particularly in the central and eastern regions, which are dominated by the Dinaric Alps. Herzegovina, the smaller, southern region, has a Mediterranean climate and is mostly mountainous. Sarajevo is the capital and the largest city.

The area has been inhabited since at least the Upper Palaeolithic, with permanent human settlement traced to the Neolithic cultures of Butmir, Kakanj, and Vučedol. After the arrival of the first Indo-Europeans, the area was populated by several Illyrian and Celtic civilisations. Most of modern Bosnia was incorporated into the Roman province of Dalmatia by the mid-first century BCE. The ancestors of the modern South Slavic peoples arrived between the sixth and ninth centuries. In the 12th century, the Banate of Bosnia was established as the first independent Bosnian polity. It gradually evolved and expanded into the Kingdom of Bosnia, which became the most powerful state in the western Balkans by the 14th century. The Ottoman Empire annexed the region in 1463 and introduced Islam. From the late 19th century until World War I, the country was annexed into the Austro-Hungarian monarchy. In the interwar period, Bosnia and Herzegovina was part of the Kingdom of Yugoslavia. After World War II, it was granted full republic status in the newly formed Socialist Federal Republic of Yugoslavia. In 1992, following the breakup of Yugoslavia, the republic proclaimed independence. This was followed by the Bosnian War, which lasted until late 1995 and ended with the signing of the Dayton Agreement.

Croatia, officially the Republic of Croatia, is a country in Central and Southeast Europe, on the coast of the Adriatic Sea. It borders Slovenia to the northwest, Hungary to the northeast, Serbia to the east, Bosnia and Herzegovina and Montenegro to the southeast, and shares a maritime border with Italy to the west. Its capital and largest city, Zagreb, forms one of the country's primary subdivisions, with twenty counties. Other major urban centers include Split, Rijeka and Osijek. The country spans 56,594 square kilometres (21,851 square miles), and has a population of nearly 3.9 million.

The Croats arrived in modern-day Croatia, then part of Roman Illyria, in the late 6th century. In the 7th century, they organized the territory into two duchies. Croatia was first internationally recognized as independent on 7 June 879 during the reign of Duke Branimir. Tomislav became the first king by 925, elevating Croatia to the status of a kingdom. During the succession crisis after the Trpimirović dynasty ended, Croatia entered a personal union with Hungary in 1102. In 1527, faced with Ottoman conquest, the Croatian Parliament elected Ferdinand I of Austria to the Croatian throne. In October 1918, the State of Slovenes, Croats, and Serbs, independent from the Habsburg Empire, was proclaimed in Zagreb, and in December 1918, it merged into the Kingdom of Yugoslavia. Following the Axis invasion of Yugoslavia in April 1941, most of Croatia was incorporated into a Nazi-installed puppet state, the Independent State of Croatia. A resistance movement led to the creation of the Socialist Republic of Croatia, which after the war became a founding member and constituent of the Socialist Federal Republic of Yugoslavia. On 25 June 1991, Croatia declared independence, and the War of Independence was successfully fought over the next four years.

The Kingdom of Montenegro was a monarchy in southeastern Europe, present-day Montenegro, during the tumultuous period of time on the Balkan Peninsula leading up to and during World War I. Officially it was a constitutional monarchy, but absolutist in practice. On 28 November 1918, following the end of World War I, with the Montenegrin government still in exile, the Podgorica Assembly proclaimed unification with the Kingdom of Serbia, which itself was merged into the Kingdom of Serbs, Croats and Slovenes three days later, on 1 December 1918. This unification with Serbia lasted, through various successor states, for almost 88 years, ending in 2006.

During this period, Montenegro remained largely rural and traditional. The constitution, adopted in 1905, provided a basic framework for governance and recognized some civil rights, such as freedom of religion and the press, but the political system remained heavily centered on the king. King Nikola maintained tight control over political life, and the state operated with only limited parliamentary influence. The society was patriarchal and conservative, with significant influence from the church and tribal customs, and few advancements in terms of modernization or civil institutions.