Sick of AI stealing provinces from me in wars

[Alpacalypse]

Every time I declare a war, some nearby country dashes in, sieges the province I want while I'm fighting and gets to keep it. How do I stop this ♥♥♥♥♥♥♥t? At this point, I've had to resort to using the console to manually control a provice whenever the ai goes into a separate war to steal it from me (which has been at least 5 times in a row, every time I declare on someone and it's always the best province they take)

[Miles]

???

I've never had this be a signifigent problem, which means you're probably doing something wrong.

What is your method of seiging provinces, and conducting war in general?

[Khorps]

you need to occupy it before anyone else does. recruit one unit and have it occupy all the provinces with the high priority ones first while your army sieges forts and fights the enemy army.