When the clubs were created in the 1800 's , Celtic fans were Catholic and Rangers Fans were Protestants .
The two teams would dominate the league , and the winner of the Old Firm would most likely win the League that year .
When the clubs were created in the 1800 's , Old Firm fans were Catholic and Old Firm Fans were Protestants .
The two teams would dominate the league , and the winner of the Old Firm would most likely win the League that year .