Integrating Junior Partner and AE

Edit: Answered

I’m Castile. I am in the process of integrating Aragon which is taking decades. I am not attacking anyone or expanding. I’m being a very well behaved, peaceful monarch. But, I am getting waves of AE. For almost 20 yrs countries are joining the coalition against me including Poland whom I’ve never had any contact with. The Pope even keeps joining. What is happening?

Edit: Answered/solved. I have been trying to see how many relatives I could get as heirs through favors. Thanks everyone especially u/Duffy171