The expulsion of Sigismund Vasa from Sweden resulted in a sixtyyear war between Poland-Lithuania and Sweden, broken only by truces of varying lengths. Not until Polish kings had lost all hope of recovering their position in the south-eastern Baltic, where they were still firmly entrenched at the end of the sixteenth century, let alone recover the throne of Sweden, to which they continued to lay claim while there was a Vasa in Warsaw,1 did they withdraw from the struggle. The contest between Sweden and Poland-Lithuania also provided an opportunity for the Elector of Brandenburg, Poland’s vassal for the duchy of East Prussia, to establish himself as an independent Baltic ruler; in 1605, in order to gain his support, the king of Poland granted elector Joachim Frederick the regency in the duchy, which would otherwise have reverted to the Polish crown.2 The collapse of authority in Muscovy at the beginning of the seventeenth century and the ensuing ‘Time of Troubles’ extended the Baltic conflict as both Poland and Sweden sought to fill the vacuum in Moscow and each to use Muscovy’s resources to win a decisive victory over the other. The revival of Muscovy under the first Romanov after 1613 enabled the country to rid itself of foreign invaders, but did not lead to an immediate resumption of the ‘drive to the sea’.