Just put all your provinces into the HRE in this way, and once you add your capital to the HRE, you will join. On the left side of your screen there is a button that lets you put the province in the HRE (It has the HRE symbol, and if you meet the requirements it should be yellow and grey if you don’t). Sunni is best in general, orthodox is really good if you’re competent, coptic is very strong if you’re going for WC. Why did vassals have to swear an oath to remain faithful to the King?.What happens when you dismantle HRE eu4?.What provinces do you need to form Germany eu4?.How do you become a Holy Roman emperor?.What happens if you Vassalize the emperor in eu4?.