Why did Roose Bolton betray Robb?

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Tags

1. #roose
2. #north
3. #which
4. #marriage
5. #control
6. #support
7. #house
8. #ambition
9. #suspected
10. #promise
11. #promised
12. #breaking
13. #horse
14. #thousand
15. #lannisters
16. #decided
17. #lannister
18. #bolton
19. #freys
20. #winning