The Treaty of Hadiach became also a major factor leading to the Commonwealth's renewed warfare with the Tsardom, which considered the accord a violation of the previously agreed truce. The approaching Russian army was defeated at Konotop in July 1659 by Vyhovsky with Polish and Tatar help. During disturbances among the Cossack masses that followed, Jerzy Niemirycz was killed. But Moscow's pressure continued and in the fall Ivan Vyhovsky was forced to give up his hetmanship and was replaced by Yurii Khmelnytsky, Bohdan's son. Khmelnytsky, in an attempt to preserve the unity of Ukraine (the left-bank Cossack regiments had already joined the Russian side), concluded a new Pereyaslav agreement with Russia on October 27. The articles substantially reduced the Ukrainian autonomy and the hetman's authority. The Kiev patriarch became a subordinate of the patriarch of Moscow. Russia's progressive incorporation of all of Ukraine was however prevented by the military developments that followed.