Mount & Blade: Warband

You should be able to unlock the Calradian Tea Party achievement at the same time but it was a bit glitchy for me. You may have to reload a save and try again for both.

There are several methods for earning this achievement which all revolve around capturing and claiming a fief for yourself then becoming faction-less. https://gaming.stackexchange.com/questions/27439/how-do-i-st...

1. Be awarded a fief (castle or town) from your current faction's king or queen then start a rebellion either by challenging the king or using your spouse (see the link above).

2. While faction-less, perform hostile actions against a faction until they become hostile towards you then capture one of their fiefs for yourself.

I also found that you can do the following.

3. Choose to help a claimant regain their rightful throne, capture and claim a fief as your own, then tell the claimant that you give up on their rebellion. I made a second save and told Arwa the Pearled One that the rebellion was a lost cause. She kicked me out of the rebellion and I unlocked the achievement. I then reloaded the other save so I could continue working on other achievements.