Few events of early modern East Slavic history have attracted as much attention or caused such public controversy as the Pereiaslav Agreement of January 1654 between Hetman Bohdan Khmelnytsky of Ukraine and the Muscovite boyars. When the Ukrainian president Leonid Kuchma, apparently trying to please his Russian counterpart Vladimir Putin, signed a decree in March 2002 to commemorate the 350th anniversary of the Pereiaslav Council, which had approved the deal from the Ukrainian side, his opponents immediately accused him of kowtowing to Russia. The decree provoked heated debates in scholarly circles and in the media. In January 2004 the Ukrainian authorities had to scale down the commemoration of the event, to the apparent displeasure of the Russian delegation, headed by President Vladimir Putin, which came to Kyiv to celebrate the “Year of Russia in Ukraine.”

What was it about the Pereiaslav Agreement that infuriated so many of Ukraine's academics and politicians, while eliciting such approval from the Russian political and academic elite? At the core of the disagreement is not so much the event itself or the hard facts of its history as its interpretation, especially in the nineteenth-century Russian Empire and its successor state, the USSR. It is no accident that President Kuchma's critics accused him of reviving the Soviet tradition of celebrating the “reunification of Ukraine with Russia” – the official formula that defined the purpose of the Pereiaslav Agreement in Soviet historiography after World War II. There were two commemorations of the event in the Soviet period.