The Gate of Felicity (Bâbü’s-saâde or Bab-üs Saâdet) is the entrance into the Inner Court (Enderûn), also known as the Third Courtyard, marking the border to the Outer Court or Birûn. The Third Courtyard comprises the private and residential areas of the palace, including the Enderûn School. The Sultan used this gate, which symbolized his might, and the Divan Meydanı square only for special events such as the accession to the throne ceremony (cülûs), the Bayram Eve Reception (Arife Divanı) - held the day before the Holy Bayram - and the Bayram Greetings Reception (Bayramlaşma Töreni). The Sultan sat before the gate on his Bayram throne on these religious and festive days, when the subjects and officials performed their homage standing.
The Gate represents the presence of the Sultan in the palace. No one could pass this gate without the authority of the Sultan. Even the Grand Vizier was only granted authorisation on specified days and under specified conditions. Considered the main door to the private quarters of the Sultan, the Gate of Felicity was kept closed at all times and an unauthorised crossing behind the gate was seen as the worst violation of the law and challenge to the Sultan’s absolute power. The gate was under the control of the Chief Eunuch of the Sultan’s Harem (called the Bâbü’s-saâde Ağası) and the staff under him. The gate had been built during the time of the initial construction of the Palace in the 15th century as a colonnaded passage with a dome supported by lean marble pillars. The rococo mask system and decorations belong to the era of Sultan Abdülhamit I and Selim III (1789-1807). The wooden ceiling dome resting on four marble columns with Ionic capitals that embodied the classical elements representative of the style referred to as Turkish Baroque, was built under Sultan Abdülhamit I (1775). The landscape frescoed architrave, the simple decorations of the ceiling and eaves, the banner ensigns on the dome and its rim reflect rather the Empire style of the Sultan Mahmut II era (1808-39). The key stone of the front façade is endowed with a besmele inscription (“In the name of God, the Most Gracious, and the Most Merciful”) and the monogram of Sultan Mahmut II in his own hand writing, as well as with inscriptions containing eulogies in verse praising Sultan Abdülhamit coupled with his monograms on the lateral façades and on the rear façade there are inscriptions with the names of the same sultans; these inscriptions constituting the documents relevant to the repairs performed on the gate by successive sovereigns throughout the years .
On either side of the gate were the quarters of the Chief Eunuch of the Sultan’s Harem (called the Bâbü’s-saâde Ağası) as well as of the White Eunuchs (Akağalar) who were responsible for the Enderûn. It opens onto the Divan Square front through a pointed-arched porch with a stalactite top dated to the 16th century.