would come here to pray. The mosque is aligned in a diagonal line in the courtyard to make the minbar face Mecca. In 1928 the books of the Enderûn Library, among other works, were moved here as the Palace Library (Sarayı Kütüphanesi), housing a collection of about 13,500 Turkish, Arabic, Persian and Greek books and manuscripts, collected by the Ottomans. Located next to the mosque to the northeast is the Imperial Portraits Collection. Dormitory of the royal pages The Dormitory of the Royal Pages (Hasoda Koğuşu) houses the Imperial Portraits Collection (Padişah Portreleri Sergi Salonu) was part of the Sultan's chambers. The painted portraits depict all the Ottoman sultans and some rare photographs of the later ones, the latter being kept in glass cases. The room is air-conditioned and the temperature regulated and monitored to protect the paintings. Since the sultans rarely appeared in public, and to respect Islamic sensitivity to artistic depictions of people, the earlier portraits are idealisations. Only since the reforms of the moderniser Mahmud II have realistic portraits of the rulers been made. An interesting feature is a large painted family tree of the Ottoman rulers. The domed chamber is supported by pillars, some of Byzantine origin since a cross is engraved on one of them. Privy Chamber The Privy Chamber houses the Chamber of the Sacred Relics (Kutsal Emanetler Dairesi), which includes the Pavilion of the Holy Mantle. The chamber was constructed by Sinan under the reign of Sultan Murad III. It used to house offices of the Sultan. It houses what are considered to be "the most sacred relics of the Muslim world": the cloak of Muhammad, two swords, a bow, one tooth, a hair of his beard, his battle sabres, an autographed letter and other relics which are known as the Sacred Trusts. Several other sacred objects are on display, such as the swords of the first four Caliphs, the Staff of Moses, the turban of Joseph and a carpet of the daughter of Mohammed. Even the Sultan and his family were permitted entrance only once a year, on the 15th day of Ramadan, during the time when the palace was a residence. Now any visitor can see these items, although in very dim light to protect the relics, and many Muslims make a pilgrimage for this purpose. The Arcade of the Chamber of the Holy Mantle was added in the reign of