Football originated as a combination of two older sports, rugby and soccer. In the 1800s, it became popular in the United States but had no set rules or regulations until the 1880s, when standardized rules were established, such as requiring teams to gain 10 yards in 4 downs or turn over the ball. By the late 1800s, key aspects of the modern game had developed, including teams of 11 players consisting of forwards, halfbacks, and fullbacks, with specific roles like quarterback; rules for tackling and scoring; and penalties to enforce regulations. Players also began wearing protective padding and equipment like helmets and cleats.