We have many posts and podcasts on the early beginnings of football on Pigskin Dispatch from its roots of Rugby and Soccer through the transformation of the 19th century into the gridiron game we love today. Many derivatives of th basic game have come about over time but one that has stayed popular for over 80 years is that of flag football. Flag football is the version of the game where basically the tackling aspect of the game is replaced by relinquishing the flag of an opponent from connection to their person.
UPDATE: Author Timothy P. Brown from the Fields of Friendly Strife website contacted me after this article posted to inform me that in his research he found that touch and flag football was actually started in 1910. The Missouri Tigers actually adopted the practice during football's brutal seasons when the escalation of deaths and injury were rampant as the forward pass was being adopted into football. Make sure to read Tim's piece of flag and touch football.
An early version of flag according to the website studentweb.cortland.edu came about in the early 1930's as a game called "Touch and Tail" football. It was a variant of two hand touch but each aooponet would stock a cloth streamer, probably a rag of some sort tucked in their britches and hanging from their backside. The objective of the defense was to remove this rag from the runner to stop play and further advancement of the ball.
The side streamers and name of flag football was developed on military bases in the early 1940's as a recreational sport for military personal. Fort Meade in Maryland is often generally-accepted as the birthplace of the streamer game in the military. In the post World War II years, recreational leagues soon sprouted up across the country by the servicemen who played it while on duty. Perhaps the most remembered of these leagues was the National Flag & Touch Football League (NTFL), which was the dominant national league for over a decade and a half.