The Deputies' Chamber and adjoining rooms
- The Room in the Great Tower - The Studio in the Great Tower - The Middle Room -
- The Former Guardhall - The Justice Court Gallery
During the rebuilding of the Mazovian dukes' Great Hall in the years 1569 – 1572, a Council Chamber (for the Deputies) was established on the ground floor.
The Deputies' Chamberseated ca. 190 deputies along benches arranged around the Marshal's chair. The vaulting is ornamented with 32 coats-of-arms of estates and provinces of the old Republic.