The Decembrist revolt () was a failed coup d'état led by liberal military and political dissidents against the Russian Empire. It took place in Saint Petersburg on , following the death of Emperor Alexander I.

Alexander's brother and heir-presumptive Grand Duke Konstantin Pavlovich privately renounced his claim to the throne two years prior to Alexander's sudden death on 1 December [O.S. 19 November] 1825. The next in the line of succession therefore was younger brother Nicholas, who would ascend the throne as Emperor Nicholas I. Neither the Russian government nor the general public were initially aware of Konstantin's renunciation, and as a result, parts of the military took a premature oath of loyalty to Konstantin. A general swearing of loyalty to the true emperor Nicholas was scheduled for in Senate Square, Saint Petersburg.

In the midst of this confusing transition into Nicholas' reign, the Northern Society, a secret society of liberal revolutionaries, nobles, and military officials, organized a conspiracy to replace the Russian Empire's autocratic regime with a constitutional monarchy. To seize control of the government and implement a regime change, it sought to convince the military that Nicholas was usurping the throne from Konstantin. On 26 December, Northern Society members led a force of approximately 3,000 troops into Senate Square to prevent the loyalty-swearing ceremony and to rally additional soldiers and officers to their cause. This group of rebels, although disorganized due to indecision and dissension among its leaders, confronted troops loyal to Nicholas outside the Senate building in the presence of a large civilian crowd. A standoff ensued, during which Nicholas' envoy, Mikhail Miloradovich, was assassinated. The loyalists eventually opened fire with heavy artillery, scattering the rebels.

In the aftermath of the coup attempt, five rebellion leaders were sentenced to hanging; many other participants were imprisoned, or exiled to Siberia. The individuals who participated in the conspiracy and coup attempt became known as the Decembrists ().

Union of Salvation and Union of Prosperity At first, many officers were encouraged by Tsar Alexander I's early liberal reformation of Russian society and politics. Liberalism was encouraged on an official level, creating high expectations during the period of rapprochement between Napoleon and Alexander. The major advocate for reform in Alexander's regime was Count Mikhail Mikhailovich Speransky. During his early years in the regime, Speransky helped inspire the organization of the Ministry of the Interior, the reform of ecclesiastic education, and strengthening the government's role in the country's economic development. Speransky's role increased greatly in 1808. From then until 1812, when they feared him as a liberal similar to Napoleon and his invasion, Speransky developed plans for the reorganization of Russia's government. Because of increasing hostility, he was forced to flee into exile.

Returning from exile in 1819, Speransky was appointed as the governor of Siberia, with the task of reforming local government. In 1818, the tsar asked Count Nikolay Nikolayevich Novosiltsev to draw up a constitution.Sherman, R and Pearce, R (2002) Pg. 23 The abolition of serfdom in the Baltic provinces was instituted between 1816 and 1819.David Moon. "The Abolition of Serfdom in Russia". Harlow: Pearson Education Limited, 2001. Page xiv However, internal and external unrest, which the tsar believed stemmed from political liberalization, led to a series of repressions and a return to a former government of restraint and conservatism.

Meanwhile, the experiences of the Napoleonic Wars and realization of the suffering of peasant soldiers resulted in Decembrist officers and sympathizers being attracted to reform changes in society.A similar liberal reaction followed the Crimean War in 1854 and resulted in the emancipation of the serfs in 1861. They displayed their contempt of court by rejecting the court lifestyle, wearing their cavalry swords at balls (to indicate their unwillingness to dance), and committing themselves to academic study. These new practices captured the spirit of the times as a willingness by the Decembrists to embrace both the peasant (i.e., the fundamental Russian people) and ongoing reform movements from intellectuals abroad.

Pavel Pestel identified reasons for reform:

Historians have noted that the United States Declaration of Independence and the American Revolution may also have influenced Decembrists, as they did other nations. The constitution written by Nikita Muravyov was highly similar to the United States Constitution. But the Decembrists were against slavery in the United States. They worked to free any slaves and serfs from all countries in Russia immediately.A. Etkind. Another freedom. Pestel and his followers opposed the United States' federal model in peaceful times as threatening to the would-be Russian/United Slavic federation; they only approved the US revolutionary model. While agreeing with Pestel that the American revolutionary model could be the best form for Russia, the would not agree to participate in establishing a federation. They wanted a United States-style republic or other state, with Lithuania, Belarus and Ukraine to be included in a unitary Poland (i.e., more or less the territory of the former Polish–Lithuanian Commonwealth), without any Russian involvement in the affairs of these territories.

In 1816, several officers of the Imperial Russian Guard founded a society known as the Union of Salvation, or of the Faithful and True Sons of the Fatherland. The society acquired a revolutionary cast after it was joined by the idealistic Pavel Pestel. The charter was similar to charters of the organizations of carbonari. Pestel was supported by Yakushkin when there were rumors that the emperor had intended to transfer the capital from Saint Petersburg to Warsaw, and to liberate all peasants without the consent of Russian landlords. They would not be able to influence a government based in Warsaw. Yakushkin intended to kill the emperor even before the revolution. When the society consisting of Russian landlords had refused to kill the emperor based on such rumors, Yakushkin left the society. The more liberal Mikhail Muravyov-Vilensky created a new charter similar to that of Tugendbund. It did not have revolutionary plans and the society was called the Union of Prosperity. It was still considered illegal and similar to masonic lodges. (The small Order of Russian knights, excepting its prominent member Alexander von Benckendorff, also joined the Union of Prosperity, together with the members of the Union of Salvation.Дружинин Н. М. Революционное движение в России в XIX веке. М., 1985. С.323. Нечкина М. В. Движение декабристов. Т.1. М., 1955. С.134.)

After a mutiny in the Semenovsky Regiment in 1820, the society decided to suspend activity in 1821. Two groups, however, continued to function secretly: a Southern Society, based at Tulchin, a small garrison town in Ukraine, in which Pestel was the outstanding figure, and a Northern Society, based at Saint Petersburg, led by guard officers Nikita Muraviev, Prince S. P. Trubetskoy and Prince Eugene Obolensky.Peter Neville (2003) Russia: A Complete History: 120–121 The political aims of the more moderate Northern Society were a British-style constitutional monarchy with a limited franchise. They envisioned that it could be replaced with a republic in the future but only according to the will of the people. They also believed there should be a legislative assembly and did not call for the execution of the imperial family. They supported the abolition of serfdom, according to the interests of Russian landlords, i.e. with land to be retained by landlords, in a style similar to the abolition of serfdom in Baltic provinces. They also supported equality before the law. The Southern Society, under Pestel's influence, was more radical and wanted to abolish the monarchy, establish a republic, similar to the Union of Salvation, and contrary to the Union of Salvation plans, to redistribute land, taking half into state ownership and dividing the rest among the peasants. The Society of United Slavs (also known as the Slavic Union – Pan-Slavism) was established in Novohrad-Volynsky (now Zviahel) in Ukraine in 1823. Its never-written program was similar to that of the Southern Society but the main emphasis was on the equal federation of Russia (including Ukraine), Poland, Moldavia (including Bessarabia) with the attachment of Wallachia, Transylvania, Hungary (including Slovakia, Slovenia, Vojvodina, the Carpatho-Ukraine aka Zakarpattia), Croatia, Serbia, Dalmatia, the Czech lands of Bohemia and Moravia, i.e. all Slavic and Vlach countries with the exception of Bulgaria and Macedonia, in the future. This society joined the Southern Society and adopted its program in exchange for the recognition of the Slavic federation zeal by the Southern society in September 1825.Горбачевский И. И. Записки. Письма. – М., 1963. Нечкина М. В. Общество соединенных славян. – М.; Л., 1927. Оксман Ю. Г. Из истории агитационно-пропагандистской литературы 20-х гг. XIX в. // Очерки из истории движения декабристов: Сб. ст. – М., 1954.

At Senate Square

When Emperor Alexander I died on , the royal guards swore allegiance to the presumed successor, Alexander's brother Konstantin. When Konstantin made his renunciation public, and Nicholas stepped forward to assume the throne, the Northern Society acted. With the capital in temporary confusion, and one oath to Konstantin having already been sworn, the society scrambled in secret meetings to convince regimental leaders not to swear allegiance to Nicholas. These efforts culminated in the Decembrist revolt. The leaders of the society elected Prince Sergei Trubetskoy as interim ruler.

On the morning of , a group of officers commanding about 3,000 men (elements of Life-Guards Moscow Regiment, Grenadier Life Guards Regiment, and Naval Equipage of the Guard) assembled in Senate Square, where they refused to swear allegiance to the new tsar, Nicholas I, proclaiming instead their loyalty to Konstantin. They expected to be joined by the rest of the troops stationed in Saint Petersburg, but they were disappointed. The revolt was hampered when it was deserted by its supposed leader Prince Trubetskoy. His second-in-command, Colonel Bulatov, also vanished from the scene. After a hurried consultation, the rebels appointed Prince Eugene Obolensky as a replacement leader.Edward Crankshaw (1978) The Shadow of the Winter Palace. London, Penguin: 14–16

For hours, there was a stand-off between the 3,000 rebels and the 9,000 loyal troops stationed outside the Senate building, with some desultory shooting from the rebel side. A vast crowd of civilian on-lookers began fraternizing with the rebels but did not join the action.Edward Crankshaw (1978) The Shadow of the Winter Palace. London, Penguin: 15–16 Eventually, Nicholas (the new tsar) appeared in person at the square and sent Count Mikhail Miloradovich to parley with the rebels. Miloradovich was fatally shot in the back by Pyotr Kakhovsky while delivering a public address, then stabbed by Yevgeny Obolensky. At the same time, a rebelling squad of grenadiers, led by Lieutenant Nikolay Panov, entered the Winter Palace but failed to seize it and retreated.