Why is Wales not on the union flag?

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Tags

1. #union
2. #instead
3. #century
4. #principality
5. #created
6. #first
7. #appear
8. #meant
9. #included
10. #could
11. #welsh
12. #england
13. #because
14. #wales
15. #already
16. #kingdom
17. #dragon
18. #united