Polish–Lithuanian–Ruthenian Commonwealth
The Polish–Lithuanian–Ruthenian Commonwealth was a proposed European state in the 17th century that would have replaced the existing Polish–Lithuanian Commonwealth.
The establishment of the Grand Duchy of Ruthenia was considered at various times, particularly during the 1648 Cossack insurrection against Polish rule in Ukraine. Such a Ruthenian duchy, as proposed in the 1658 Treaty of Hadiach, would have been a full-fledged member of the Polish–Lithuanian Commonwealth, which would thereby have become a tripartite Polish–Lithuanian–Ruthenian Commonwealth. In May 1659, the Polish Diet ratified the treaty with an emended text.
The idea of a Ruthenian Duchy within the Commonwealth was completely abandoned. Canadian historian Paul Robert Magosci believes that this happened due to divisions among the Cossacks and to the Russian invasion;
however, both these events occurred much earlier than the signing of the Treaty of Hadiach. The Russian historian Tairova-Yakovleva regards the resistance of Polish society and papal pressure as the reasons for the incomplete ratification.
The idea of a Polish–Lithuanian–Ruthenian Commonwealth revived during the January Uprising when a patriotic demonstration took place at Horodło in 1861. The so-called Second Union of Horodło was announced there, by the szlachta of Congress Poland, of the former Grand Duchy of Lithuania, of Volhynia and of Podolia. New Poland, based on the Second Union of Horodło, was to be based on the three nations, and its proposed coat of arms included the Polish eagle, the Lithuanian Pahonia, and the patron saint of Ruthenia, the Archangel Michael.
