text: who invented american football and when?   both american football and soccer have their origins in varieties of football played in the united kingdom in the mid-19th century, and american football is directly descended from rugby football.  mcgill university athletes, who had learned rugby from the local british army garrison, introduced the sport to the u.s. with a game against harvard university in 1874. the game quickly spread to other ivy league colleges.  encouraged by yale university's walter camp, the schools began to adopt rules that would differentiate american football from rugby in the 1880s. the scrimmage was introduced in 1880 and the system of downs in 1882.  by the turn of the 20th century, football had become notoriously dangerous; 18 college players died in 1905 alone. colleges responded with a series of rule changes to open up the game, most importantly the forward pass, along with outlawing dangerous formations such as the "flying wedge", and introducing and requiring better equipment such as helmets.  the game had achieved its modern form by 1912, when the field was changed to its current size, the value of a touchdown increased to 6 points, and a fourth down added to each possession. originally dominated by the ivy league, football soon captured the interest of colleges nationwide. by 1916, when the rose bowl game matching eastern and western teams became an annual event, football had developed a national following second only to baseball among team sports.  professional football developed in the mill towns of pennsylvania and the american midwest in the early years of the 20th century. the nfl was founded in 1920 in canton, ohio. professional football remained a largely regional sport of secondary importance until after world war ii. television broadcasts greatly enhanced nfl football's national appeal, and the pro game surpassed both college football and baseball in popularity in the 1960s. the first super bowl—between the champions of the nfl and the rival american football league—was played in 1967, and the two leagues merged in 1970