Shah Jahan's Apartment. The royal apartments of Shah Jahan are situated to the south of the white marble Khas Mahal set transitionally inbetween the two major residential complexes of two different periods. Shah Jahan first attempted to convert the existing red sandstone building to suit his refined taste. It consists of a spacious hall and a side room with an octagonal tower overlooking the river. The interior constructed in lakhauri bricks and sandstone veneering with white stuccoed in fine lime plaster which is colourfully painted with vegetal motifs. The entire palace originally glittered like white marble. Looking towards Khas Mahal, there is a large spacious dalan (verandah) of white marble, composed of nine cusped arches, supported on double pillars and protected externally by wide eaves (chhajja). The eastern gallery tower is built of red sandstone. Its western chamber is closed by transparent mirrors to view Ghazni Gate. The so-called Babur's stepped well is situated beneath it. The subterranean apartments in seven storeys and the so-called Phansi Ghar are also located under this complex.
The central pavilion on the large platform at the back of the Diwan-i-Khas is Shah Jahan's sleeping apartment better known as Khas Mahal but in the contemporary historical literature it is mentioned as Aramgah (or khwabgah) or place of rest. Flanking it on either side are two almost similar rectangular pavilions (in the form of palanquin) with three arched openings within a screened enclosure overlooking the river. From the northern one Shah Jahan presented himself from the central arched opening to the public outside the Fort, a daily ceremony current from the time of Emperor Akbar which was famous as Jharoka Darshan.
These rectangular pavilions are surmounted by curved sloping eaves and standing Bangala roofs which are guilded in gold on copper sheets covering the roofs. Abdul Hamid Lahori the contemporary historian who was Shah Jahan's official chronicler, records that when the Emperor presented himself to his subjects under this guilded golden roof (Roshan Ara Pavilion) it appeared as if there were two suns. One was light from the morning sun reflected on the roof of this pavilion. The other was the Emperor himself. Light reflected from the gold roof appeared to crown the Emperor with a halo of the sort after depicted in contemporary paintings and described in literature.
The almost similar rectangular pavilion on the other side of the Aramgah (Jahan Ara Pavilion) was said to have been used by Princess Jahan Ara Begum, eldest daughter of Emperor Shah Jahan, popularly called Begum Sahib. She was also declared as chief of the harem after the death of Mumtaz Mahal in 1631. She was also entrusted with the royal seal Muhr-i-udak which was earlier kept by Mumtaz Mahal and which solemnized all the farmans and royal orders.
There are several chambers on the southern side of the Khas Mahal which face a rectangular pavilion with an arcuate embellished ceiling. Its eastern platform has a deep reservoir with a fountain, which creates a rainbow in the atmosphere when filled with coloured water and the fountain functions. On three sides of the Anguri Bagh there are double storied square chambers most probably used by the royal ladies.
The rectangular garden has (marble) stone laid out plan inside the garden. This was originally full of plants of sweet fragrance flowers. It seems after some time later grapes were grown in this garden, which gave the name Anguri Bagh. The garden has an opening in the western wall.