The Pereyaslav Articles (Ukrainian: Переяславські статті, romanized: Pereiaslavski statti, Russian: Переяславские статьи, romanized: Pereyaslavskiye stati) were concluded on 27 October 1659 between Yurii Khmelnytsky, the son of Bohdan Khmelnytsky, and the Russian tsar.
Under the new articles, the Zaporozhian Cossacks were not allowed to conduct any foreign policy, including military alliances.
[2] Under the treaty, Russian military governors and garrisons were placed in Bratslav, Chernihiv, Nizhyn, Pereiaslav, and Uman (previously, they had been only in Kiev since 1654).
[1] In addition, the Cossacks could no longer elect their own hetmans or colonels without the approval of the Tsar.
The treaty led to popular unrest and later influenced Khmelnytsky's decision to ally with Poland in 1660.