The only reason I have ever heard is that the skins didn't want the cowboys in pro football. Somehow, the cowboys owner obtained the rights to the redskins "Hail to the Redskins" fight song and used it as ransom for the skins to agree to play them in pro ball. Don't take this as fact, though... do some more research.
cowboys
The Redskins' divisional rivals are; the New York Giants, the Philadelphia Eagles and, the Dallas Cowboys.
dallas cowboys, New York giants, Washington redskins
The big D, little d rivalry between Dallas and Denver will always be a classic. nope it is the Washington Redskins and the Philadelphia Eagles Dallas and Denver were never rivals and probably never will be. The Cowboys rivals currently are: Washington Redskins, Philadelphia Eagles, New York Giants, and Pittsburgh Steelers. Also who can forget that the Arizona Cardinals were once in the NFC East. San Francisco 49ers were a strong rival and of course the Houston Texans. Dallas has the most rivals in history because of such a winning record.
The first-ever meeting of the NFL rivals was on October 9, 1960 at Griffith Stadium in Washington. The Redskins won, 26-14.
Rivals Dallas and Washington have played each other in season openers nine times. The Cowboys are 6-2-1 in those games.
Cowboys > Patriots > Redskins > Giants > Eagles
Redskins
NFC east: every team in the division is rivals with everyone!!!!!!! (4 teams in division are: cowboys, giants, redskins, eagles)
the cowboys
The Dallas Cowboys.
On Monday, September 26, 2011, the Dallas Cowboys edged the Washington Redskins, 18-16, at Cowboys Stadium in Arlington, Texas. It was the Cowboys\' fifth victory in their last six meetings with their NFC East rivals. Dallas leads the overall series 61-40-2, which includes regular-season and postseason contests.