East Slavs Kievan Rus' Orthodox Christianity Byzantine Empire Grand Duchy of Moscow Tsardom of Russia Russian explorers Russian Empire third-largest empire in history Russian Revolution Russian SFSR socialist state Russian Civil War Soviet Union Soviet republics expense of millions of lives rapid industrialisation in the 1930s Allies of World War II Eastern Front Cold War United States most significant Russian technological achievements first human-made satellite first human expedition into outer space Russian Moscow
The East Slavs emerged as a recognisable group in Europe between the 3rd and 8th centuries CE. The first East Slavic state, Kievan Rus', arose in the 9th century, and in 988, it adopted Orthodox Christianity from the Byzantine Empire. Rus' ultimately disintegrated, with the Grand Duchy of Moscow growing to become the Tsardom of Russia. By the early 18th century, Russia had vastly expanded through conquest, annexation, and the efforts of Russian explorers, developing into the Russian Empire, which remains the third-largest empire in history. However, with the Russian Revolution in 1917, Russia's monarchic rule was abolished and eventually replaced by the Russian SFSR—the world's first constitutionally socialist state. Following the Russian Civil War, the Russian SFSR established the Soviet Union with three other Soviet republics, within which it was the largest and principal constituent. At the expense of millions of lives, the Soviet Union underwent rapid industrialisation in the 1930s, and later played a decisive role for the Allies of World War II by leading large-scale efforts on the Eastern Front. With the onset of the Cold War, it competed with the United States for global ideological influence; the Soviet era of the 20th century saw some of the most significant Russian technological achievements, including the first human-made satellite and the first human expedition into outer space.
