Did Siciński act alone? A new look at the causes of the rupture of the Sejm in 1652

More than half a century ago, it has been proven that the author of the first practical application of the liberum veto institution was Władysław Siciński during the Winter Sejm of 1652. The opinion presented by the senior Polish parliamentarian researcher of the mid-17th century, Ludwik Kubala, about the reasons of the breakdown of the discussed Sejm has been fixed. It was pointed out to Janusz Radziwiłł’s activity, which was to use Siciński for his own political games. For over a hundred years, the position presented by Kubala has not been challenged, even though it does not have sufficient reasoning in the sources. It can not be ruled out that the current hypothesis is correct, but it is also necessary to look at other possible reasons for the precedential application of the liberum veto institution.