In the 15th century, the grand princes of Moscow went on gathering Russian lands to increase the population and wealth under their rule. Under the rule of Ivan III (1462-1505), the Grand Duchy of Moscow tripled its size by annexing the Novgorod Republic and the Principality of Tver. In development of the Third Rome ideas, Grand Prince Ivan IV the Terrible was officially crowned the first Tsar of Russia, rule from 1547 to 1584. During his long reign, Ivan nearly doubled the already large Tsardom by annexing the Khanates of Kazan, Astrakhan, and Siberia. Through these conquests, Russia was transformed into a multiethnic, multidenominational and transcontinental state.
The death of Ivan's sons marked the end of the ancient Rurik Dynasty in 1598 and followed by a period of civil wars and foreign intervention known as the "Time of Troubles" (1606–13). Polish-Lithuanian Commonwealth occupied parts of Russia, including Moscow. In 1612, the Poles were forced to retreat by the Russian volunteer corps, led by merchant Kuzma Minin, Prince Dmitry Troubetskoy, and Prince Dmitry Pozharsky. Russia then became an elective monarchy from 1613 to 1661 under the rules of three elected Tsars: Troubetskoy (1613–1625), Pozharsky (1625–1642) and Boris Morozov (1642–1661). After Morozov's death, he placed his son-in-law, Alexei Romanov, as the hereditary Tsar of Russia, established the Romanov Dynasty that ruled until 1917.
Much of Russia's expansion occurred in the 17th century, culminating in the first Russian settlement of the Pacific in the mid-17th century, the incorporation of Left-bank Ukraine and the pacification of the Siberian tribes. In 1648, the Bering Strait between Asia and North America was passed for the first time by Fedot Popov and Semyon Dezhnyov.
Under Peter I the Great (1682–1725), Russia was proclaimed an Empire in 1721 and became recognized as a world power. Peter defeated Sweden in the Great Northern War and ceded West Karelia and Ingria that lost by Russia in the Time of Troubles, as well as Estonia and Livonia that securing Russia's access to the sea and sea trade. On the Baltic Sea, Peter founded a new capital called Saint Petersburg. Peter the Great's reforms brought considerable Western European cultural influences to Russia.
The reign of Peter I's daughter Elizabeth in 1741–62 saw Russia's participation in the Seven Years' War (1756–63). During this conflict, Russia annexed most of eastern part of Prussia, including Berlin. However, upon Elizabeth's death, all these conquests were returned to Kingdom of Prussia by Peter III of Russia that hold a pro-Prussian stance.
Under Catherine II the Great (1762–96), Russia entered its Age of Enlightenment. Catherine successfully waged war against the Ottoman Empire and advanced Russia's southern boundary to the Black Sea. As a result of victories over the Ottomans, by the early 19th century Russia also made significant territorial gains in Transcaucasia. She also extended Russian political control over the Polish-Lithuanian Commonwealth and incorporated most of its territories into Russia during the Partitions of Poland, pushing the Russian frontier westward into Central Europe. This continued with Alexander I's (1801–25) wresting of Finland from Sweden in 1809 and of Bessarabia from the Ottomans in 1812. At the same time Russians colonized Alaska and even founded settlements in California, like Fort Ross.
During the height of its rule, the French Empire was expanding into the Russian western border. In the middle for his preparation to invade the British isles, Napoleon concluded a non-aggression treaty with Alexander I, guaranteed the French rule over Prussian Poland through the French client state, the Duchy of Warsaw. However, while kept its neutrality during the Napoleonic War, Russia secretly supported Britain against France. Nevertheless, following the failure of French invasion to Britain, Prussia became increasingly aggressive to expand its rule eastward. Prussia's attempts to take the Duchy of Warsaw came into conflict with Russia, resulted to the Russo-Prussian War in 1813. Prussia and Russia finally concluded the war on the Congress of Vienna in 1815, where Prussia gained most of Polish-Lithuanian lands.
The loss of Russian Poland to Prussia triggered a liberal movement in Russia that attempted to curtail the Tsar's powers during the abortive Decembrist Revolt of 1825. At the end of the conservative reign of Nicolas I (1825–55), a zenith period of Russia's power and influence in Europe was once again disrupted by the defeat in the Crimean War. Between 1847 and 1851, a massive wave of Asiatic cholera swept over Russia, claiming about one million lives.
When Alexander II (1855–81) ascended the throne, he enacted significant changes in the country, including the emancipation of serfs 1861. Although serfdom was abolished, since its abolition was achieved on terms unfavorable to the peasants, revolutionary tensions were not cooled down, despite Alexander II's intentions. Nevertheless, these Great Reforms spurred industrialization and modernized the Russian army. Alexander II invaded Outer Manchuria from the Qing Dynasty between 1858–1860 and sold Russian America to the United States in 1867. Bulgaria was also successfully liberated from Ottoman rule in 1877–78 Russo-Turkish War.
The late 19th century saw the rise of various socialist movements in Russia. Alexander II was killed in 1881 by revolutionary terrorists, and the reign of his son Alexander III (1881–94) was less liberal but more peaceful. Unlike his father, Alexander III was a staunch reactionary that intensified the Tsarist absolute rule in Russia throughout his reign. During his reign, Russia declared the union with the French Republic to contain the growing power of the German Empire, completed the conquest of Central Asia and demanded important territorial and commercial concessions from China.
The last Russian Emperor, Nicholas II (1894–1917), was unable to prevent the events of the Russian Revolution of 1905, triggered by the unsuccessful Russo-Japanese War and the demonstration incident known as Bloody Sunday. The uprising was put down, but the government was forced to concede major reforms, including granting the freedoms of speech and assembly, the legalization of political parties, and the creation of an elected legislative body. Migration to Siberia increased rapidly in the early 20th century, particularly during the Stolypin agrarian reform. Between 1906 and 1914 more than four million settlers arrived in that region.
In 1914, Russia entered World War I in response to Austria-Hungary's declaration of war on Russia's ally Serbia, and fought across multiple fronts while isolated from its Triple Entente allies. Later, military failures and bureaucratic ineptitude soon turned large segments of the population against the government. The German and Ottoman fleets prevented Russia from importing supplies and exporting goods through the Baltic and Black seas.
By the middle of 1915, the impact of the war was demoralizing. Food and fuel were in short supply, casualties kept occurring, and inflation was mounting. Strikes increased among low-paid factory workers, and the peasants, who wanted land reforms, were restless. Meanwhile, public distrust of the regime was deepened by reports that a semiliterate mystic, Grigori Rasputin, had great political influence within the government. All this formed the climate for the Russian Revolutions of 1917, that leading to the establishment of Soviet Union, the first communist nation in the world.