Polish-Lithuanian succession The idea was first broached in the 16th century, after the death of the last
King of Poland and
Grand Duke of Lithuania of the
Jagiellon dynasty,
Sigismund II Augustus.
Czar Ivan IV of Russia ("the Terrible") became a popular candidate among the
Polish nobility. He had substantial support in Poland, especially among the lesser and the middle nobility, which saw in him an opportunity to limit the growing power of the
Polish-Lithuanian magnates. During the
interregnum, two
diplomatic missions (led by
Great Scribe of Lithuania Michał Harraburda and
Jędrzej Taranowski) were sent to Moscow to hold discussions. The negotiations failed because of hostilities resulting from the
Livonian War, territorial demands by Ivan (who wanted former territories of
Kievan Rus', which was under the control of
Lithuania) and the decision by Ivan that the Russian side would not "lower itself to the level of other European monarchies and send a diplomatic mission to Poland begging for him to become a king". During the second interregnum, in 1574, the candidature of Ivan IV was even highly regarded in Poland, but the Moscow diplomatic mission that arrived in Poland had no orders or prerogatives to negotiate that matter. Eventually, the disappointed pro-Ivan faction, represented by
Jan Sierakowski, issued a statement in the Sejm: "The Great Prince of Muscovy would be the best choice for king, but because of his silence we are forced to forget him and should not mention him again".
Russian succession The mixed circle of proponents of the idea saw an opportunity in Russia after the death of Ivan the Terrible, the last Russian ruler of the time whose legitimacy was never questioned. The proposal was revived soon after Ivan's death through the reigns of
Stefan Batory in the Commonwealth and
Feodor I in Russia. After Batory's death in 1587, Feodor I became interested in acquiring the Polish-Lithuanian throne and sent a diplomatic mission to Poland. His support among the Lithuanians was high, but Poles issued several demands, such as requiring Fedors's conversion to
Catholicism, an entirely unthinkable event. Eventually,
Sigismund III Vasa was elected the king of Poland and grand duke of Lithuania. The death of Feodor prompted Sigismund to propose his candidacy for the Moscow throne, but by the time the diplomatic mission arrived in Moscow,
Boris Godunov had been elected as the new Czar.
Proposal of the last Commonwealth's king Finally, the idea returned in the 18th century, when the last Polish king and Lithuanian grand duke,
Stanisław August Poniatowski, attempted to save the Commonwealth by proposing a marriage between himself and
Russian Empress Catherine the Great. The very possibility that such an idea could have been seriously considered by the Polish side early on was likely based on the spirit of the 1573
Warsaw Confederation (Warsaw Compact), which guaranteed, at least formally, equality for non-Catholic nobles in the Commonwealth. However, the adopted convention was an unprecedentedly liberal act for its time, such full equality was never achieved in reality even within the Commonwealth itself. Taking into account that most divisions of the time, if not dynastic ones, were religious and the relationship between the Catholic and the Eastern Orthodox
branches of Christianities were strained at best, it remains surprising that such an idea was seriously considered at all. It remains equally unlikely that such an idea could have been accepted by the Russian side because the view towards Catholicism in the Russian Empire was highly negative. Thus, while the idea of a Polish–Lithuanian–Muscovite Commonwealth was supported early on by some progressive and secular Polish diplomats, the efforts of the few could not in the end overcome Russian opposition to Catholicism and the fear that such a union would spell Catholic domination over Orthodoxy. ==See also==