How do you enter a personal union?

[Akira112]

I know it has something to do with a Royal marriage but other then that I'm clueless.

[★Bandiera Rossa☭]

http://www.paradoxian.org/eu3wiki/Personal_union It has to do with having high relations, a royal marriage, their king dying, and a fair amount of luck.

[Yoda Twin]

i find being under a union can nearly ruin your game sometimes

[Akira112]

Does being in a Union allow you to inherit the other country or is that something else, because in my current game as Portugal, I got a message saying that Sweden inherited Norway.

[John I Tzimisces]

Does being in a Union allow you to inherit the other country or is that something else, because in my current game as Portugal, I got a message saying that Sweden inherited Norway.

Basically what you need to make sure is that after you get into a personal union, you need to make sure you stay in the personal union after your king dies. In order to do this you need A. positive prestige and B. positive relations (it's either positive relations or higher than 100 or 50 or something, I can't remember). Every time your monarch dies and you fulfill conditions to allow you to stay in union with a country (I mean of course with you leading the union), there's a...10% chance I believe you'll inherit the nation you're in the union with. Unlike diploannexing you get cores on all of their provinces as well (I think even the ones they don't have cores on).

Also, don't worry if you're stuck under a union led by someone else: the game is hardcoded that player nations can't be inherited that way.

A good tactic for staying in a personal union is to have a larger army than the nation you're leading in the union. If you aren't more powerful than they are, they're obviously going to resent it a lot more, and the AI will be very prone to sending insults to lower relations so they'll be freed when your monarch dies.