The Russo-Persian War of 1826–1828 was the last major military conflict between the Russian Empire and Qajar Iran, which was fought over territorial disputes in the South Caucasus region.
Initiated by Russian expansionist aims and intensified by Iranian resistance, the war witnessed significant military engagements, including the Battle of Ganja and Capture of Erivan. The Iranians were initially successful, catching the Russian forces of Yermolov off-guard. They were aided by local uprisings against Russian garrisons in Talish, Ganja, Shirvan, Shakki, and other areas. However Russian reinforcements under the newly appointed General Ivan Paskevich turned the war decisively in Russia's favor, capturing the important city of Tabriz in northwestern Iran.
The war concluded with the Treaty of Turkmenchay in 1828, which stripped Iran of its last remaining territories north of Aras river in the Caucasus, which comprised all of modern Armenia, the Nakhchivan Autonomous Republic in the Republic of Azerbaijan and the Iğdır Province in Turkey. The treaty also allowed Russia a say in Iranian politics, as the Iranian shah (king) now required Russia's acknowledgment of the person he wanted to name as heir apparent.
Iran was potentially saved from further loss and submission, possibly even from losing all of Iranian Azerbaijan or even becoming a Russian vassal, either due to the persistence of the Iranian negotiators with the help of the British or the Russians' desire to quickly make peace since another war with the Ottomans was likely nearing. After the war, the Qajar state would never again face Russia on an equal footing or be treated as an equal by European countries.
Fath-Ali Shah Qajar (r. 1797–1834), the second shah (king) of Iran's newly found Qajar dynasty, was embroiled in a conflict with Russia over the Caucasus as soon as he came to power in 1797. After many years of being subject to Iranian rule, the Christian Kingdom of Kartli-Kakheti (located in Eastern Georgia) decided to reject their rule. It made the decision to look to Russia for defense against Iran after rejecting rule by the Qajars. Since the previous shah Agha Mohammad Khan Qajar (r. 1789–1797) had been slain in the Caucasus during a military campaign, this was an important matter for the Qajar dynasty.
The reign of the Russian tsar (emperor) Alexander I (r. 1801–1825) saw an increased desire on the part of the Russians to increase their presence and influence in the Caucasus, where they had already shown interest since the 1760s. Any infringement of Iran's control over the Caucasus was not something that the Qajar administration could just ignore. Since 1502, Iran had controlled the Caucasus and the Iranians saw it as a natural extension of their country. The war of 1804–1813 soon erupted between the two countries as result of the Russian invasion of the Iranian city Ganja and massacre of its residents.
The Iranians ended up losing the war and were forced to sign the Treaty of Gulistan. Per the terms of the treaty, Iran conceded to Russia the sultanates of Shamshadil, Qazzaq, Shuragol, and the khanates of Baku, Derbent, Ganja, Shakki, Quba, Shirvan, Karabakh, and the northern and central part of Talish. Moreover, Iran also had to abandon its claims over Georgia.
The treaty's territorial arrangements were unclear, for example, in Talish, where it was left up to the mutually appointed administrators to "determine what mountains, rivers, lakes, villages, and fields shall mark the line of frontier." If one of the participants to the treaty felt that the other party had "infringed on" territorial possessions claimed in accordance with the status quo principle, even the limits laid forth in the treaty could be changed. This essentially ensured that territorial conflicts would persist after the treaty's authorization. The region between Lake Gokcha and the city of Erivan remained one of the most disputable.
In early 1825, the northern bank of Lake Gokcha, which the Iranians believed to be a part of their realm, was seized by the Russians under the orders of Aleksey Petrovich Yermolov, the governor of Georgia. The Russian army soon advanced further, capturing Balagh-lu as well. The Iranians knew that these locations might be used as a staging ground for an attack on Erivan, therefore the significance of this went far beyond the sites themselves. Although Yermolov conceded that this was Iranian territory, he defended his action by claiming that Iran was clinging to a large portion of Karabakh. The Russians also constructed a small fort on the frontier with Erivan, which the Qajar crown prince Abbas Mirza protested against.
In the middle of 1825, the fort was attacked by the troops of the Iranian governor of the Erivan Khanate, Hossein Khan Sardar. In 1826, reports of Alexander I's sudden death in late 1825 made it to Iran, but the stories that made it there exaggerated the chaos surrounding the handover of power. As a result, in December 1825, a group of young men, primarily military officers, staged the Decembrist Revolt in an attempt to force political concessions by obstructing Alexander's second younger brother Nicholas from succeeding to the throne. The rebellion was promptly put down by troops who supported Nicholas. On 8 July, the Russians captured the town of Bash Aparan in the northern Erivan Khanate, deep within Iranian territory. The Iranian American historian Maziar Behrooz considers that the start of the war of 1826–1828. In Fath-Ali Shah's court, two factions had developed during the course of building policy toward Russia. One faction advocated for peace with Russia, and the other for war. Both were heavily lobbying Fath-Ali Shah and Abbas Mirza. The first question at hand was what to do if Russia did not stop their occupation of Gokcha and Balagh-lu. The state of the Muslim minority under Russian authority and, lastly, whether and to what extent Russia had been weakened as a result of its internal crises, were secondary concerns.
Those who advocated for peace were the foreign minister Mirza Abolhassan Khan Ilchi; the chief scribe Neshat Esfahani; the head of the royal office Manuchehr Khan Gorji; and the court translator and envoy Mirza Saleh Shirazi. In general, the peace party feared the capability of the Russian Empire and wanted armed conflict to be avoided at all costs. They were more accustomed to dealing with people from other cultures and knew more about Russia.
Those who advocated for war were several prominent Islamic scholars led by Agha Sayyed Mohammad Esfahani; Fath-Ali Shah's new chief minister Asef al-Dowleh; Abbas Mirza's close advisor Abol-Qasem Qa'em-Maqam II; and some of the exiled khans of the Caucasus, who had either been driven away by the Treaty of Gulistan or had fled to Iran after the treaty. The main stance of the war party was that the Russians had clearly insulted the Iranians and been aggressive towards them. Agha Sayyed Mohammad, who was on his way to meet Fath-Ali Shah, mentioned Fath-Ali Shah's responsibilities "both as Sovereign of Persia, and as the head of the Mohamedian faith" in a letter to Fath-Ali Shah. Agha Sayyed Mohammad also brought up the Russian annexation of Iranian territory and the treatment of Muslims. Furthermore, the war party's interpretation of Russian events was more optimistic than realistic, arguing that Russia was weak overall, especially in the Caucasus due to Yermolov's recent defeats and the Decembrist revolt.
To advise Fath-Ali Shah and formulate a course of action in this matter, the Council of Soltaniyeh gathered. The peace party at Fath-Ali Shah's court was ultimately outmanoeuvred and the final decision was to launch full-scale warfare against the Russians.
Despite Abbas Mirza's soldiers appearing to be unprepared for a large fight, Iran's entry into the war in the summer of 1826 started out successfully. This was due to two factors. Yermolov was initially embroiled in a struggle in Chechnya despite advocating for war; as a result, his men were unprepared for the war and were incapable to meet the approaching challenge. Second, with the support of their previous khans, the Muslim populace rose against Russians, as they had grown tired of being oppressed. In Shirvan, Ganja, Talish, Shakki and Karabakh (aside from Shusha), the stationed Russian troops were either driven out by the rebels or Iranian forces, or withdrew themselves. It is uncertain if rebellions occurred or were suppressed in Quba, Baku, Derbent and Georgia.