Polish–Lithuanian–Muscovite Commonwealth
The first proposal of the union was made in the 16th century, when the last king of the then ruling Polish Jagiellon dynasty died. Many people in the Polish-Lithuanian Commonwealth wanted the Commonwealth to be ruled by Tsar Ivan IV of Russia ("the Terrible"). Ivan offered to decrease the power of the Polish-Lithuanian magnates (high nobility in the Polish-Lithuanian Commonwealth). Two diplomatic missions were sent from Poland to Moscow, which both failed due to the two sides not being able to agree on a compromise. This was due to the earlier Livonian War (where the Tsardom fought the Commonwealth) and Tsar Ivan's demands of the former territory of Kievan Rus, which Lithuania held. Eventually, negotiations were dropped, and the pro-Ivan faction in the Commonwealth agreed to stop supporting Ivan in becoming the king.