During the East German era, 1. FC Union Berlin was known for a rivalry with BFC Dynamo, which was reputedly affiliated with the powerful state security service of East Germany (Stasi). Union was supported by the regional district administration of the governing SED party and sponsored by local state-owned enterprises. The club played some identificatory role in the unofficial opposition against the authorities of the communist system. Between 1979 and 1988, BFC Dynamo won ten consecutive East German league titles, with popular allegations of sporting misconduct helping to fuel the rivalry, and clashes between both sets of fans occurred. BFC Dynamo was seen as the supreme representative of the security agencies, with advantages in the recruitment of players and financial support as well as the political clout of Erich Mielke. Supporters of Union cultivated the image of their club as the eternal underdog that was firmly rooted in the working class. Union became the most popular club in East Berlin.