The present invention provides a foundation for a wind turbine. To reduce set-up time and to allow complete alignment of the platform which carries the base flange of the tower construction, the invention provides a foundation with a cage structure having an upper stress distribution flange connected by a plurality of tensioned anchor bolts to a lower flange. The flanges are separated by a number of distance elements whereby the shape of the cage structure becomes fixed by the combination between tensioned bolts and distance elements. Since the cage structure has a fixed shape, the upper stress distribution flange can be aligned before the cage structure is embedded in concrete, and it becomes unnecessary to wait for the concrete to harden.