A war between them saw supporters of one found the Bar Confederation.
One of these two nations intervened in the other after the Tarnogrod Confederation agitated for a "silent" legislative session. They fought the Battle of Klushino when the king of one of them, Sigismund III, invaded the other, in a war concluded at the Peace of Deulino. A war between them saw supporters of one found the Bar Confederation. Another war between these two nations was known as the "Deluge" in one of them. A successor state to one of these nations perpetrated the Katyn Forest Masscre on citizens of the other. For 10 points, name these two countries, one of which was led by Catherine the Great when it partitioned the other.
One of these two nations intervened in the other after the Tarnogrod Confederation agitated for a "silent" legislative session.
{Russian Empire} and {Kingdom} of {Poland} [for “{Russia},” accept {Rossiyskaya Imperiya}; for “{Poland},” accept any of the {following}: {Polish}-{Lithuanian Commonwealth}; or {Union} of {Lublin}; or {Polska}]