Ukraine and Russia share much of their history. Kiev, the modern capital of Ukraine, is often referred to as a mother of Russian Cities or a cradle of the Rus’ civilisation owing to the once powerful Kievan Rus’ state, a predecessor of both Russian and Ukrainian nations.
 
 
Muscovy and Russian Empire  
After the Mongol invasion of Rus the histories of the Russian and Ukrainian people’s started to diverge. The former, having successfully united all the remnants of the Rus’ northern provinces, swelled into a powerful Russian state. The latter came under the domination of the Grand Duchy of Lithuania, followed by the Polish-Lithuanian Commonwealth. Within the Commonwealth, the militant Zaporozhian Cossacks refused polonization, and often clashed with the Commonwealth government, controlled by the Polish nobility. Unrest among the Cossacks caused them to rebel against the Commonwealth and seek union with Russia, with which they shared much of the culture, language and religion. which was eventually formalized through the Treaty of Pereyaslav in 1654. From the mid-17th century Ukraine was gradually absorbed into the Russian Empire, which was completed in the late 18th century with the Partitions of Poland. Soon afterward in the late 18th century the Cossack host was forcibly disbanded by the Empire, with most of the population relocated to the Kuban region in the South edge of the Russian Empire, where the Cossacks served a valuable role of defending the Empire against the fierce Caucasian tribes.
 
Soviet Union  
The February Revolution saw establishment of official relations between the Russian Provisional Government and the Ukrainian Central Rada that was represented at the Russian government by its commissar Petro Stebnytsky. At the same time Dmitriy Odinets was appointed the representative of Russian Affairs in the Ukrainian government. After the Soviet military aggression by the Soviet government at the beginning of 1918, Ukraine declared its full independence from the Russian Republic. The two treaties of Brest-Litovsk that Ukraine and Russia signed separately with the Central Powers calmed the military conflict between them and peace negotiations were initiated the same year.
 
After the end of the World War I, Ukraine became a battleground in the Russian Civil War and both Russians and Ukrainians fought in nearly all armies based on their political belief.
 
In 1922, Ukraine and Russia were two of the founding members of the Union of Soviet Socialist Republics, and were the signatories of the treaty that terminated the union in December 1991.
 
In 1932-1933 the Ukraine experienced the Holodomor (Ukrainian: Голодомор, “Extermination by hunger” or “Hunger-extermination”; derived from ‘Морити голодом’, “Killing by Starvation”) which was a man-made famine in the Ukrainian Soviet Socialist Republic that killed up to 7.5 million Ukrainians. During the famine, which is also known as the “Terror-Famine in Ukraine” and “Famine-Genocide in Ukraine”, millions of citizens of Ukrainian SSR, the majority of whom were Ukrainians, died of starvation in a peacetime catastrophe unprecedented in the history of Ukraine. Since 2006, the Holodomor has been recognized by the independent Ukraine and several other countries as a genocide of the Ukrainian people. Scholars disagree on the relative importance of natural factors and bad economic policies as causes of the famine and the degree to which the destruction of the Ukrainian peasantry was premeditated on the part of Joseph Stalin. Using Holodomor in reference to the famine emphasizes its man-made aspects, arguing that actions such as rejection of outside aid, confiscation of all household foodstuffs, and restriction of population movement confer intent, defining the famine as genocide; the loss of life has been compared to the Holocaust. If Soviet policies and actions were conclusively documented as intending to eradicate the rise of Ukrainian nationalism, they would fall under the legal definition of genocide. In the absence of absolute documentary proof of intent, scholars have also made the argument that the Holodomor was ultimately a consequence of the economic problems associated with radical economic changes implemented during the period of liquidation of private property and Soviet industrialization.
 
Third Reich armies invaded the Soviet Union on 22 June 1941, thereby initiating four straight years of incessant total war. The Axis allies initially advanced against desperate but unsuccessful efforts of the Red Army. In the encirclement battle of Kiev, the city was acclaimed as a “Hero City”, because the resistance by the Red Army and by the local population was fierce. More than 600,000 Soviet soldiers (or one-quarter of the Soviet Western Front) were killed or taken captive there.
 
Although the majority of Ukrainians fought alongside the Red Army and Soviet resistance, in Western Ukraine an independent Ukrainian Insurgent Army movement arose (UPA, 1942). Primarily it was created as forces of Ukrainian Government in exile but soon it fell under the influence of nationalist underground (Organization of Ukrainian Nationalists, OUN) which had developed in interwar Poland as a radical reaction on the Polish politics towards Ukrainian minority. Both supported the goal of an independent Ukrainian state on the territory with Ukrainian ethnic majority. Although this brought conflict with Third Reich, at times the Melnyk-wing of OUN allied with the Reich forces. Some UPA divisions also carried out the massacres of ethnic Poles, which caused also relatively smaller Polish actions in response. After the war UPA continued to fight the USSR till 1950s. Using guerrilla war tactics, the insurgents targeted for assassination and terror those who they perceived as representing or cooperating with the Soviet state.
 
The republic was heavily damaged by the war, and it required significant efforts to recover. More than 700 cities and towns and 28,000 villages were destroyed. The situation was worsened by a famine in 1946–47, which was caused by a drought and the wartime destruction of infrastructure. The death toll of this famine varies, with even the lowest estimate in the tens of thousands.
 
In 1945, the Ukrainian SSR became one of the founding members of the United Nations organization, part of a special agreement at the Yalta Conference.
 
The first Soviet computer, MESM, was built at the Kiev Institute of Electrotechnology and became operational in 1950.
 
On 26 April 1986, a reactor in the Chernobyl Nuclear Power Plant exploded, resulting in the Chernobyl disaster, the worst nuclear reactor accident in history. This was the only accident to receive the highest possible rating of 7 by the International Nuclear Event Scale, indicating a “major accident”, until the Fukushima Daiichi nuclear disaster in March 2011. At the time of the accident, 7 million people lived in the contaminated territories, including 2.2 million in Ukraine.
 
After the accident, the new city of Slavutych was built outside the exclusion zone to house and support the employees of the plant, which was decommissioned in 2000. A report prepared by the International Atomic Energy Agency and World Health Organization attributed 56 direct deaths to the accident and estimated that there may have been 4,000 extra cancer deaths.
 
Independent Ukraine  
On 16 July 1990, the new parliament adopted the Declaration of State Sovereignty of Ukraine. This established the principles of the self-determination, democracy, independence, and the priority of Ukrainian law over Soviet law. A month earlier, a similar similar declaration was adopted by the parliament of the Russian SFSR. This started a period of confrontation with the central Soviet authorities. In August 1991, a conservative faction among the Communist leaders of the Soviet Union attempted a coup to remove Mikhail Gorbachev and to restore the Communist party’s power. After it failed, on 24 August 1991 the Ukrainian parliament adopted the Act of Independence.
 
A referendum and the first presidential elections took place on 1 December 1991. More than 90% of the electorate expressed their support for the Act of Independence, and they elected the chairman of the parliament, Leonid Kravchuk as the first President of Ukraine. At the meeting in Brest, Belarus on 8 December, followed by the Alma Ata meeting on 21 December, the leaders of Belarus, Russia, and Ukraine, formally dissolved the Soviet Union and formed the Commonwealth of Independent States (CIS).
 
Ukraine was initially viewed as having favorable economic conditions in comparison to the other regions of the Soviet Union. However, the country experienced deeper economic slowdown than some of the other former Soviet Republics. During the recession, Ukraine lost 60% of its GDP from 1991 to 1999, and suffered five-digit inflation rates. Dissatisfied with the economic conditions, as well as the amounts of crime and corruption in Ukraine, Ukrainians protested and organized strikes.