Union of Russia and Ukraine Tercentenary in the context of "Transfer of Crimea in the Soviet Union"

The Pereiaslav Agreement or Pereyaslav Agreement (Ukrainian: Переяславська рада, romanized: Pereiaslavska Rada, lit. 'Pereiaslav Council', Russian: Переяславская рада) was an official meeting that convened for a ceremonial pledge of allegiance by Zaporozhian Cossacks to Russian tsar Alexis (r. 1645–1676) in the town of Pereiaslav in central Ukraine, in January 1654. The ceremony took place concurrently with ongoing negotiations that started on the initiative of Hetman Bohdan Khmelnytsky to address the issue of the Cossack Hetmanate with the ongoing Khmelnytsky Uprising against the Polish–Lithuanian Commonwealth and which concluded the Treaty of Pereiaslav (also known as the March Articles). The treaty itself was finalized in Moscow in April 1654 (in March according to the Julian calendar).

Khmelnytsky secured the military protection of the Tsardom of Russia in exchange for allegiance to the tsar. An oath of allegiance to the Russian monarch from the leadership of the Cossack Hetmanate was taken, shortly thereafter followed by other officials, the clergy and the inhabitants of the Hetmanate swearing allegiance. The exact nature of the relationship stipulated by the agreement between the Hetmanate and Russia is a matter of scholarly controversy. The council of Pereiaslav was followed by an exchange of official documents: the March Articles (from the Cossack Hetmanate) and the tsar's declaration (from Russia).