What is the history of El Clasico?

Related questions

1. How many goals does Messi have in El Clasico?
2. What countries are Celtic?
3. Has Celtic won 9 in a row?
4. Is El Clasico a derby?
5. What race were the Celts?
6. When did Barcelona win 6 cups?
7. Is Celtic the same as Gaelic?
8. How can I buy Barcelona FC tickets?
9. How much do FC Barcelona tickets cost?
10. Who has more trophies Real Madrid or Barcelona?

Tags

1. #barcelona
2. #gamper
3. #along
4. #social
5. #history
6. #abridged
7. #center
8. #spaniards
9. #several
10. #political
11. #foreign
12. #founded
13. #madrid
14. #players
15. #considered
16. #spain