1869 The teams of Princeton and Rutgers played a soccer football game on November 6th, using modified London Football Association rules. Rugby was being favored with major eastern schools over soccer duruing the next several years. After modern American football began to devlope from rugby.
1876 Walter Camp attended the Massasoit convention where he would write the first rules for American Football. He is known as the father of the NFL  
1893 The Pittsburgh Athletic club signs one of its first players. Grant Dibert is thought to be the first player to ever sign a contract in the game of American Football.
1895 John Brallier is the first player to turn pro with accepting $10 and expenses. He played for the Latrobe YMCA.  
1896 The Allegheny Athletic Association is the first team to field and complete a professional 2-game season.  
1898 A touchdown was changed from 4 points to 5 points  
1899 Small neighborhood team was formed from the Morgan Athletic Club. This team went through a series of names until 1994 when it was officially named the Arizona Cardinals.
1904 A field goal was set from 5 points down to 4.  
1906 Forward pass is legalized.  
1909 Field goal dropped from 4 points to 3.  
1912 Touchdown is incraesed from 5 points to 6.  
1941 NFL headquarters are moved.  
1947 A new official is added to the number of refs called the back judge.  
1954 Joe Perry becmomes the first in the leagues history to gain 1,000 rushing yards in consecutive seasons.
1955 Sudden-death overtime rule is used for the time. It was a pre-season game between the Rams and Giants at Portland.  
1960 A new NFL Commissioner is selected named Pete Rozelle on January 26.  
1965 NFL pledges to not accept college seniors until they have completed all of their games.  
The remaining years leading up to 2017 only had information about superbowls, team conflict, and many things that weren't too important to how the game was set up.