The Third Courtyard (The Inner Palace / Enderûn Courtyard) is like the keep of a castle: when the gates to this courtyard (surrounded by strong structures) are shut, entry is virtually impossible. The courtyard covers an area of approximately nine “dönüm” (decares), with one “dönüm” (decare) equaling roughly 900 square meters.
Upon entering the courtyard from the Gate of Felicity, the first building one sees is the Audience Chamber (Arz Odası) stood at the centre of the courtyard. This is where the sultan received the grand vizier, other viziers, and ambassadors. Located immediately behind the Audience Chamber is the Library of Sultan Ahmed III which stands like an elegant jewel box in the midst of this grand space. On the right side of the courtyard are the Inner Palace
At Topkapı, the Enderûn—which means “the inner part of the palace” or “the Inner Palace” in Persian—began at the Gate of Felicity. It consisted of the residences of the sultan, the white eunuchs in his service, and other court dignitaries, in addition to the various dormitories and barracks around the courtyard, where court education was carried out. The Audience Chamber, where the sultan received the grand vizier, other viziers, and ambassadors, stood at the center of the courtyard. Also located here is the library built by Sultan Ahmed III, which stands like an elegant jewel box in the midst of this grand space.
School (Enderûn Mektebi), the Campaigners’ Barracks, the Conqueror’s Pavillion (Fâtih Köşkü) and the remains of a bathhouse dating to the time of Sultan Selim II (r. 1566-74). On the left side of the Inner Palace Courtyard are the Privy Room (Has Oda), which houses the Holy Mantle of the Prophet (Hırka-i Saâdet) and other holy relics; the Privy Room Dormitory; and the Mosque of the Aghas of the Inner Palace. On the two sides of the Gate of Felicity are located the Greater and the Lesser Chambers of the Inner Palace, the White Eunuchs’ Dormitory, and the Apiary. Opposite the gate and across the courtyard, are the Treasury of the Chamberlain, the Dormitory of the Treasury and the Butlers’ Dormitory.