The Baltic League was founded in 1640 by king Erik XVII of Sweden, Northern Norway and Mecklenburg together with Prussia, Brandenburg-Silesia and Franconia-Pomerania. Originally considered as a defense against Polish or Russian threats, the League soon started to become a counterweight to the interests of French king François IV, and his allies in the Alliance des Alpes, in the HRE.
1680, league member Heinrich IV of Brandenburg died. His son was unable to govern, which he was aware of. So he decided that Brandenburg-Silesia should be governed by a collegium of the other rulers of the Baltic League (Kristina I of Sweden, Johann IX of Hohenzollern and Balthasar II of Prussia) until there'd be a capable heir to take over.
Surprisingly, in 1681 Johann IX of Hohenzollern (of Franconia-Pomerania) died without heirs too. The new French king François V declared the collegial government over Brandenburg-Silesia and Franconia-Pomerania for illegal.
The leaders of the Baltic League stood up to the challenge, and queen Kristina would start to form a bigger alliance directed against France with England, Spain and Sicily; the traditionally anti-French Netherlands already were at her side, thanks to her marriage to Dutch royal Eduard of Wassenberg, later Eduard IV.
In 1682, the (several times postponed) election for Holy Roman Emperor happened. (Several candidates, like crown prince Humphrey of England and king Humphrey I himself, had died at an inconvenient time, and the anti-French groups had had to look for new candidates, since queen Kristina of Sweden wasn't electable.) Finally, after a turbulent election, king Francisco of Sicily was elected emperor Franz IV by Brandenburg, Prussia, Saxony, Jülich-Berg, the Netherlands, Palatinate (until then controlled by France), while François V ("the other Franz", as the Germans called him) was elected by Poland, Württemberg-Austria, Nassau, Braunschweig and Luxemburg. François V didn't want to accept the result of the election, which was admittedly quite unclear (are the votes of French-occupied Luxemburg and collegially governed Brandenburg valid?). As a result, the anti-French War started.
| Prominent Rulers|
(founding members in italics)