The conflict between Azerbaijan and Armenia over the Nagorno-Karabakh region was one of the most controversial issues in the modern history of the South Caucasus. Nagorno-Karabakh is a historical territory of Azerbaijan, and most of the population has been ethnic Azerbaijanis for the past several centuries. The Armenian population became prominent only in the last two centuries, following the settlement of Armenians in this region as a result of treaties signed between the Russian Empire and the Qajar Empire and between the Russian Empire and the Ottoman Empire at the beginning of the nineteenth century.

Although the Versailles Peace Conference recognized Nagorno-Karabakh as part of the Azerbaijan Democratic Republic of 1918–1920, Armenia did not abandon its claim to the territory. After two years of controversies between Azerbaijan and Armenia, when the South Caucasus countries became part of the Soviet Empire at the beginning of the 1920s, Nagorno-Karabakh was again flagged as a topic of discussion. Therefore, while referring to pre-existing reality, the plenum of Kavbiuro CC RCP(b) (Caucasus Bureau of the Central Committee of the Russian Communist Party) decided to leave Nagorno-Karabakh within the territory of Azerbaijan Soviet Socialist Republic according to the decree of July 5, 1921. Further, in 1923, it was granted with an autonomous status. During the Soviet time, the Armenian side appealed to the center of the Soviet Union with the hope of annexing Nagorno-Karabakh Autonomous Oblast (NKAO) to the Armenian SSR. However, each time the Soviet authority rejected their illegal attempts. After Mikhail Gorbachev’s perestroika (reconstruction) and glasnost (openness) and policies in the Soviet Union, Armenia’s long-standing desire to annex the NKAO found new momentum and provided the country with the opportunity to express its territorial claims towards Azerbaijan openly.

On the eve of the collapse of the Soviet Union at the end of the 1980s, the Regional Soviet of Nagorno-Karabakh decided to transfer the region to the sovereignty of Armenian SSR, which was rejected not only by Azerbaijan SSR but also by the Supreme Soviet of the USSR and the Central Committee of the Communist Party of the Soviet Union (CPSU) with reference to the Article 78 of the USSR Constitution. Article 78 clearly signified that territorial alterations were unacceptable without the agreement of the affected Union Republic. Despite this, Armenians of Nagorno-Karabakh followed a secessionist policy and began to create their political structures with the direct support of the Armenian SSR. They elected a Congress of Authorized Representatives of the Population of the NKAO in the summer of 1989. The congress was comprised exclusively of Armenian deputies, elected by local soviets or village councils. On 24 August 1989, the congress elected National Council, featuring 78 members, and its Presidium became the de facto government of Nagorno-Karabakh. Furthermore, the Armenian side used the Soviet Law of 3 April 1990, “On the Procedures for Resolving Questions Related to the Secession of a Union Republic from the USSR,” as a legal basis to justify its separatist actions. These endeavors explicitly violated not only the above-mentioned article of the Soviet Constitution but also the 1990 April Law per se. However, from that time on, Armenians possessed an unconstitutional government over the region.

The First Karabakh War that broke out after Azerbaijan and Armenia gained their independence as a result of the collapse of the Soviet Union in 1991 and ended with the Russian-brokered ceasefire of May 1994 had a devastating result for Azerbaijan. Thus, Armenia occupied 20 percent internationally recognized territory of Azerbaijan, and around one million Azerbaijanis lost their property and faced forced migration as a result of the ethnic cleansing policy of Armenia against Azerbaijanis that were living not only in the occupied territories of Azerbaijan but also in the territories of today’s Armenia for centuries.

From the ceasefire agreement of 1994 until the outbreak of the Second Karabakh War of 2020, there were various peace initiatives by different states and international and regional institutions. However, all these initiatives failed due to the Armenian side’s destructive approach to the negotiation process. During the years of occupation of the territories of Azerbaijan, the Armenian side wanted, as it worded, “to use the power of facts (i.e., military control) to maintain the de facto status and change the de-jure status” in order to get recognition of the former Nagorno-Karabakh region as an independent state or unify it with Armenia. However, with the counter-offensive operation along the entire front to the Armenian aggression against Azerbaijan, on September 27, 2020, Azerbaijani Army started the liberation of the territories that Armenia had occupied in the wake of the First Karabakh War of the early 1990s. The war that lasted 44 days and was labeled as ‘the Patriotic War’ or the ‘44-day War’ depicted the Azerbaijani Army’s strength and ended with Azerbaijan’s decisive victory. Azerbaijan’s anti-terror operation of September 19–20, 2023, signifies the complete reinstatement of Azerbaijani sovereignty over its entire officially recognised territory.

In light of the above-mentioned factors and developments, this study is intended to introduce the main historical, political, and legal facts and arguments regarding the Karabakh region in general and the former Nagorno-Karabakh conflict in particular as a collection to the readers. Each of the presented materials is scientifically substantiated and developed by the authors in detail according to local and international sources, documents, and treaties. The facts, ideas, and opinions in this portal are presented to the reader with appropriate scientific references. It consists of 99 different questions and answers regarding the Karabakh region and the Nagorno-Karabakh conflict from historical, political, and legal aspects and contains the main documents and treaties mentioned within the study.