The Römer has been the town hall of the city of Frankfurt am Main since the 15th century and, with its characteristic stepped gable façade, is one of its landmarks. As the centre of city politics, it is the seat of the city representatives and the Lord Mayor. The middle building of the originally three independent buildings on Römerberg is the actual Haus zum Römer. For centuries, the term "Römer" has been used to refer to the entire city hall complex. Why the central building is called "Römer" is unknown; there are various, contradictory interpretations.