Why is Northern Ireland separated from southern Ireland?

Related questions

1. What did the IRA want?
2. Why did Ireland want home rule?
3. Is the IRA from Northern Ireland?
4. How long has the IRA been fighting?
5. Did Ireland support the IRA?
6. Who signed the Solemn League and Covenant?
7. Are unionists Catholic?
8. Why did Britain keep Northern Ireland?
9. What did Northern Irish Protestants mean by the phrase Home Rule is Rome Rule?
10. Is Northern Ireland mostly Catholic or Protestant?

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2. #remained
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4. #which
5. #break
6. #became
7. #british
8. #northern
9. #republic
10. #ninety
11. #people
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13. #violence
14. #living
15. #ireland
16. #called
17. #rulers
18. #south
19. #after
20. #unrest
21. #split
22. #state
23. #years
24. #their
25. #against