A multi-circuit hydraulically closed braking system includes at least two wheel brakes, which are each associated with a braking circuit, two multi-circuit pressure generators, which are connected hydraulically in series between a fluid container and the at least two wheel brakes, and a hydraulic unit for hydraulic connection of the pressure generators to the at least two wheel brakes and for individual brake pressure modulation in the at least two wheel brakes. A first pressure generator is configured as a plunger system and is associated with a primary system which comprises a first power supply and a first evaluation and control unit for controlling the first pressure generator. A second pressure generator is configured as a pump system and is associated with a secondary system, which comprises a second power supply, independent of the first power supply, and a second evaluation and control unit.