Alexander's I sudden death changed the plans of conspirators and forced them to act before the planned term.
Cesarevich Konstantin was considered a successor of the throne after Alexander I. His letter to the emperor about a voluntary renunciation the 4th of January 1822 and the manifest of the 16th of August 1823, proclaiming the rights of grand duke Nikolay Pavlovich on the Russian throne, were kept in secret. Under the insistence of the dignitaries not knowing the secret of the 27th of November 1825, the armed forces and the population were submitted to the oath to emperor Konstantin I.
Only the 12th of December 1825, official confirmation of renunciation of the throne came from Konstantin , who was living in Warsaw. The manifest about the accession of emperor Nikolay I immediately followed and the ceremony of inthronization was fixed on the 14th of December 1825. The interregnum displeased people and army. The moment for realization of plans of secret societies was extremely favorable. Besides it, Decembrists knew that the government received a report about their activity, and the 13th of December, Pestel was arrested in Tulchina.
The plan of revolution was approved during the meetings of the members of the society in Ryleev's apartment in St. Petersburg. Crucial importance was given to the success of the demonstration in the capital. In the south of the country, the armies were supposed to act simultaneously in the 2nd army. One of the founders of the revolt, S.P.Trubetskoy, the colonel of the guards, participant of the war of 1812, known and popular among the soldiers, was elected dictator of the revolt. The 14th of December, it was decided to introduce the armed forces in the Senatorial area in order to prevent the oath of the Senate and the State council to Nikolay I and from their name to promulgate " the Manifest to Russian people ", proclaiming the cancellation of the serfdom, freedom of a seal, conscience, employment and movement, and also the introduction of a general compulsory military service instead of recruitment by force. The government appeared deposed, and the authority passed to the provisional Government until the acceptance by a representative of the Great Council of the decision concerning the form of board in Russia. The imperial family should be arrested, the Winter palace and the Peter and Paul Fortress were supposed to be occupied with the help of armies, and Nikolay was supposed to be killed.
But it was not possible to execute that plan. A.I.Yakubovich, who should command the sea Guards crew and the Ismailov regiment, while capturing the Winter palace and arresting the members of the imperial family, refused to carry out this task from fear to become the initiator of the tsar's murder. The Moscow's gentleman-at-arms regiment, joined later by the sailors and the Life Guards (about 3 thousand soldiers and 30 officers), appeared at the Senator's square. While Nikolay I pulled the army to the square, general Miloradovich addressed to the revolutionists a message in which he asked them to break-up, and he was deathly wounded. It was soon found out, that Nikolay had already received the swears of the members of the Senate and the State council. It was necessary to change the plan of revolt, but S.P.Trubetskoy, called to supervise the actions, at the decisive moment showed cowardice and didn't appear at the square. Towards evening, the Decembrists chose a new dictator, the prince Obolensky; but time was missed.
Nikolay I, after several unsuccessful attacks of the cavalry, ordered to shoot the insurrection forces with case-shoot of guns. That day, 1271 persons were killed, and the majority of victims (more than 900 persons) were curious and sympathizing people who met up at the square. The 29th of December 1825, S.I.Muraviev-Apostol and M.P.Bestuzhev-Rumin could lift up the regiment of Chernigov standing in the south, in village of Trilesy. The governmental armies were directed against the revolutionists. The 3rd of January 1825, Chernigov regiment was crushed.
579 officers were involved in the investigation supervised by Nikolay I himself; 280 of them were recognized guilty. The 13th of July 1826 K.F.Ryleev, P.I.Pestel, S.I.Muraviev-Apostol, M.P.Bestuzhev-Rumin and P.G.Kakhovsky were hung up. Other Decembrists were degraded, banished to hard labours in Siberia and in the Caucasian regiments. The soldiers and sailors (2,5 thousand persons) were judged separately. Part of them was sentenced to punishment by rods (178 persons), sticks and birches; the others were sent to Caucasus in a field army and to Siberia.