a first housing comprising any of the following: a master brake cylinder having at least one piston enabled to be acted on with force by a brake pedal; a travel simulator of an electronic brake pedal; or a brake switch for fully automated driving,

one or more pressure supply devices, wherein at least one of the pressure supply devices is a piston-cylinder unit driven by an electromotive drive or is a double-action piston pump driven by an electromotive drive, wherein the electromotive drive is arranged to adjust the piston of the piston pump or double-action piston pump directly or via a transmission gear,

one or more valve arrangements with solenoid valves,

one or more electronic open-loop and closed-loop control units,

wherein the brake system has at least two hydraulic circuits, and wherein a pressure change is enabled to be performed, using a pressure supply device of the one or more pressure supply devices, in at least one wheel brake assigned to one of the hydraulic circuits, wherein at least one of the one or more valve arrangements and at least one piston and pressure chamber of at least one of the one or more pressure supply devices are arranged in a second housing, and wherein the second housing is connected to the first housing;

wherein the actuating device is a 2-box solution with two modules, wherein:

the first module comprises at least one of the one or more pressure supply devices, at least one of the one or more valve arrangements, at least one of the one or more open-loop and closed-loop control units and a reservoir, wherein the at least one of the one or more open-loop and closed-loop control units is of fully or partially redundant configuration; and

the second module comprises the first housing;

wherein the actuating device further comprises a further pressure supply device with continuous delivery action, wherein the further pressure supply device is arranged either in the second housing or in a further housing, together with an associated valve arrangement;

wherein the first module comprises an electronic control unit (ECU) housing comprising at least one of the one or more open-loop and closed-loop control units and having two mutually separate on-board electrical system connections, one for the at least one pressure supply device and the other one for the further pressure supply device.