On June 19, 1943, the NFL approved a merger between the Philadelphia Eagles and the Pittsburgh Steelers for the 1943 season because of a player shortage due to World War II. There was talk of the league shutting down completely, as more than 300 players had left their respective teams to serve on the largest team they would ever be a part of . The official name for the team was the Philadelphia Eagles Pittsburgh Steelers Combine, the official name didn't stick very long at all as the fans and the writers began to call them the "Steagles" it was a nickname that stuck. Both teams had not been very good up to that point, in fact the Eagles had never had a winning season and Pittsburgh had only one winning season to their credit, so expectations were low to say the least. They surprised everyone as they posted a 5-4-1 record and fell just short of winning the Eastern Conference. The team would have been considered a ragtag bunch, some players were only able to make the squad because of different medical conditions that kept them from being drafted. These men would work 40 hours a week in factories for the defense industry, practice at night, then play ball on Sunday's. Perhaps the most memorable game of that season came in the second game as the Steagles upset the New York Giants 28-14 even though they had fumbled the ball 10 times in the contest, the 10 fumbles in one game is a record that still stands today. I find this fact remarkable as it shows how the country came together in a time of war, the men who played on that Steagles team not only brought Philadelphia their first winning season, they also brought much needed joy to the fans in both cities as their fathers, brothers, and sons were fighting for the country. The merger came to an end following the '43 season, the Steelers combined forces with the Chicago Cardinals the next year and had rough season as the team that was nicknamed the "Carpets" went 0-10. The Eagles continued to get better following the '43 campaign, they would eventually win back to back championships in '48 and '49 with several of the players from the Steagles on those championship squads.
Bleacher Report did a great video that gives you a look into the team: http://www.youtube.com/watch?v=uU_vZzaSh14