The Outer Treasury building, which is currently used as Weapon Section, was initially constructed under Sultan Mehmet II (the Conqueror) (1451-81), and later demolished along with the former Council Hall and replaced by a new building erected between 1526 and 1528 during the time of Sultan Süleyman the Magnificent. The structure is covered with eight domes resting on three big buttresses pillars.
The Outer Treasury building has been used as official state treasury up until mid-19th century.
The taxes levied from the country and from the provinces, resources originating from military campaigns, the furs and caftans to be bestowed upon ambassadors (hil’at), silk and gold brocade robes, sable-lynx furs and the old registers of the Council Hall were safe-kept in this building. The trimonthly salaries (ulûfe) of the janissaries and cavalry soldiers (Sipahi) andthe military campaign and navy expenditures, and the salaries of civil servants of the central administration were borne by this treasury. The Outer Treasury, which was under the responsibility of the Treasurer (Defterdar) was sealed off and closed by affixing the seal of the Sultan that was conserved by the Grand Vizier.