I'm playing EU4 on latest patch (Rule Britannia) as GB, I went Anglican religion. I want to become Emperor of the HRE and to do that I need to have neither Catholic nor Protestant win the religious war – have the war end without either side demanding religious supremacy.
Naturally I joined the league war against the emperor, but I'm not the leader since I'm not protestant.
What can I do to steer the war towards Peace of Westphalia?
Best Answer
Your natural reaction was indeed the wrong one in this case.
To get the peace of westphalia the religous league war must either end with a peace treaty not specifying supremacy (e.g. by completely exhausting both war leaders) or go on for a very long time (25-30 years) to end automatically.
To ensure this as an outsider, you should have stayed neutral, watched the league war and intervene for the losing side, when necessary to create a balance of power until the war ends. Or, if you are strong enough, declare war on both leagues and conquer them to force the leaders to end the league war inconclusively.
In your current situation, your only hope is for the catholic side to be naturally stronger, so you can only intervene, when necessary to prevent the protestants from losing. If the protestants are naturally stronger, there is nothing you can do.