Why is the Welsh flag a dragon?

Related questions

1. Why is there a dragon on the Welsh flag?
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4. Do flagpoles need to be grounded?
5. Was Lancelot a real person?
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Tags

1. #dragon
2. #state
3. #officially
4. #included
5. #bosworth
6. #national
7. #welsh
8. #descent
9. #recognised
10. #royal
11. #henry
12. #battle
13. #carried
14. #which
15. #cathedral
16. #tudor
17. #signify
18. #their
19. #after
20. #supporter