Battle of Warsaw was one of the biggest battles of Deluge, fought 28-30 July 1656. It ended in Swedish-Brandenburgian victory, say that this fact is not changed in TTL, but despite victory both Sweden and Brandenburg lost their leaders (Charles X really was wounded in that battle, so making his wound a bit worse is not big challenge. Battlefield is not particulary safe place, so something bad could as well happen to Elector of Brandenburg). So what would be result? After the news of death of both monarchs spread, John Casimir may decide to not abandon Warsaw, Deluge should end much faster-Sweden lost king (and new one is infant) and skilled commander. Support for Charles Gustav in Poland and Lithuania should melt much faster than IOTL. Brandenburg also goes to little kid (son of Frederick William is just two years old). Death of Great Elector isn't good news for Brandenburg-he just started process of changing Brandenburg to great power status, but his reforms are fresh and many not yet done, so that process should slow down (Frederick William was not called Great Elector without a reason) and that is not all-after experience of Elector's treason next Hohenzollern would not be allowed to inherit Ducal Prussia (Prussians, drained by Hohenzollerns from their resources, would not have much reason to complain about it-before all, Sigismund III allowed Brandenburgian Hohenzollerns to inherit Ducal Prussia against will of Prussian estates, which preffered direct incorporation into PLC).
So how much would be Brandenburg hurt by loss of one of its most capable rulers and loss of eastern province?
So how much would be Brandenburg hurt by loss of one of its most capable rulers and loss of eastern province?