Short answers, pulled from the story.
The Dayton Triangles won what is considered the first game of the American Professional Football Association (later the NFL), defeating the Columbus Panhandles 14-0 on the 3rd of October, 1920, at Triangle Park in Dayton, Ohio.
The Dayton Triangles took their nickname from Triangle Park, their home field located at the confluence of the Great Miami and Stillwater Rivers in north Dayton, Ohio.
Earle "Greasy" Neale served as player-coach during the Triangles' 1918 Ohio League Championship season and was inducted into the Pro Football Hall of Fame in 1969. Other notable players included Arthur Matsu and Sneeze Achiu in the late 1920s.
On the 12th of July, 1930, a Brooklyn syndicate led by Bill Dwyer and Jack Depler purchased the Triangles and relocated them to Brooklyn as the Brooklyn Dodgers. The franchise passed through several more relocations and renamings before the player contracts eventually ended up with the Baltimore Colts in 1953, who moved to Indianapolis in 1984.
The Dayton Triangles franchise passed through Brooklyn, Boston, New York, and Dallas before its assets were absorbed into the Baltimore Colts in 1953. The NFL officially considers the Colts a 1953 expansion team and does not recognize a lineage from the Triangles. The Colts are based in Indianapolis, 117 miles west of Dayton.
The Dayton Triangles were charter members of the American Professional Football Association in 1920. They finished their inaugural NFL season 5-2-2 and were one of only three original NFL franchises, along with the Bears and Cardinals, to survive the entire 1920s. From 1923 through 1929 they won only five of 51 NFL contests.