Emperor Nicholas I was born on June 25 (July 6) 1796 and was the third son of Paul I and Maria Feodorovna. He received a good education but showed no interest in the humanities, preferring military arts and fortification. Nicholas was also a skilled engineer.

In 1817, he married the Prussian princess Frederica-Louise-Charlotte-Wilhelmine, known as Alexandra Feodorovna, who was the mother of the future Emperor Alexander II.

Nicholas I ascended to the throne after the death of his elder brother Alexander I. The second claimant, Constantine, renounced his rights while Alexander was still alive, but Nicholas was unaware of this and initially swore allegiance to Constantine. This period was later called the interregnum. Although the manifesto announcing Nicholas I's accession to the throne was issued on December 13 (25), 1825, his reign legally began on November 19 (December 1). On the very first day of his reign, the Decembrist uprising occurred on Senate Square, which was suppressed, and its leaders were executed in 1826. This event prompted Nicholas to initiate reforms aimed at organizing the laws, relying on officials as trust in the nobility had been undermined.

Nicholas I's domestic policy was extremely conservative; he actively defended autocracy. The Secret Chancellery, led by Benkendorf, was engaged in political surveillance. In 1826, a censorship statute was adopted, banning all publications with political content.

Nicholas I's reforms were limited. Legislation was systematized, and under Speransky's guidance, the Complete Collection of Laws of the Russian Empire began to be published. Kiselev implemented a reform of the administration of state peasants, providing them with land when relocating to new areas, building medical facilities, and introducing agricultural innovations. From 1839 to 1843, a financial reform was conducted, establishing a ratio between the silver ruble and the assignation. However, the issue of serfdom remained unresolved.

Nicholas I's foreign policy was also aimed at combating revolution. From 1826 to 1828, after the Russo-Iranian War, Armenia was annexed to Russia. Nicholas condemned revolutionary processes in Europe and in 1849 sent Paskevich's army to suppress the Hungarian revolution. In 1853, Russia entered the Crimean War, but as a result of the Paris Peace of 1856, it lost the right to have a fleet and fortresses on the Black Sea, as well as Southern Moldavia. These failures undermined Nicholas I's health, and he died on March 2 (February 18) 1855 in St. Petersburg. His son, Alexander II, ascended to the throne.