Polish–Lithuanian–Muscovite Commonwealth

The Polish–Lithuanian–Muscovite Commonwealth was a proposed state that would have been based on a personal union between the Polish–Lithuanian Commonwealth and the Tsardom of Russia. A number of serious attempts, by various means, to create such a union took place between 1574 and 1658, and even as late as the latter part of the 18th century, but it has never materialized due to incompatible demands from both sides.

The proposed union is known in Polish historiography as the Triple Union (unia troista) and has also been called the Polish–Russian Union (unia polsko-rosyjska) or Polish–Muscovite Union (unia polsko-moskiewska). No well-established term for this entity exists in English-language histories.

Proponents of such a union among the Polish nobility, included the then influential secular thinkers Jan Zamoyski and Lew Sapieha, had listed several arguments in its favor: peace on the turbulent eastern border, a powerful military ally and relatively sparsely populated territories (compared to the Polish Crown) for colonization and serfdom. The idea was also supported by the Jesuits and other papal emissaries who never ceased to entertain the idea of bringing Orthodox Russia into the Catholic fold. Some of the Russian boyars found the proposal attractive (like Boris Godunov, a supporter of Tsar Feodor's I candidacy) for various reasons, among them the fact that the Golden Freedoms of the Commonwealth, if applied in Russia, would weaken tsar's power and thus grant the Russian nobility a much higher status than they had enjoyed previously.

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