The territory of future Ukraine, Belarus, and Russia was once covered by various principalities with their capitals in the major cities.
After their invasion of the Russian lands, the Mongols formed the Golden Horde. At the same time, Lithuanian princes created the Grand Duchy of Lithuania, the largest political entity in Eastern Europe.
In 1569, the Grand Duchy of Lithuania and the Kingdom of Poland together formed a commonwealth known as the Rzeczpospolita (“republic” in Polish). A century earlier, the Crimea had split from the Golden Horde and become a vassal of the Ottoman Empire.
After a 13-year war between Russia and the Polish-Lithuanian Commonwealth over the territory of modern Ukraine and Belarus, 1667 saw the conclusion of a truce at Andrusovo: the Commonwealth ceded Smolensk, Left-Bank Ukraine, and some other lands to Russia. Right-Bank Ukraine and Belarus remained under the control of the Commonwealth.
In the second half of the 18th century, the Polish-Lithuanian Commonwealth was no longer independent. Its kings were elected under the influence of the Russian Empire, and Prussia had its eyes on the western lands. In 1772, 1793, and 1795, the Commonwealth underwent a series of partitions, after which it ceased to exist. After the partitions, Russia absorbed the Lithuanian, Belarusian, and Ukrainian lands. And in 1791, the Ottoman Empire handed over the Crimea to Russia.
In 1807-1813, the Duchy of Warsaw existed under the protectorate of the Napoleonic empire, formed from Polish territories ceded to Prussia and Austria during the partition of 1795. At the Congress of Vienna (1814-1815) following Napoleon's defeat, most of the lands of the Duchy of Warsaw were allotted to Russia under the name of the Kingdom of Poland.
On November 20, 1917, Kiev proclaimed the Ukrainian People’s Republic, which was followed by the declaration on December 12, 1917, of the Ukrainian Soviet Republic in Kharkov and on November 1, 1918, of the West Ukrainian People’s Republic in Lviv. In 1919, they were merged into the single Ukrainian Soviet Socialist Republic.
In 1939, the Soviet Union annexed Eastern Galicia, and in 1940 Northern Bukovina and Southern Bessarabia became part of the Ukrainian SSR. In 1945, the Czechoslovakian territory of Subcarpathia was subsumed into the Ukrainian SSR, and in 1954 the RSFSR transferred the Crimea to the Ukrainian SSR.
On 24 August, 1991 the Ukrainian parliament adopted the Act of Independence in which the parliament declared Ukraine as an independent democratic state. On March 16, 2014, a referendum was held in Crimea. The final results of the referendum in Crimea show that 97 percent of voters have supported leaving Ukraine to join Russia.