This superb domed gateway was bouilt by Ala-uddin Khilji, and is declared by General Cunningham to be "the most veautiful specimen of Pathan architecture that I have seen," while Fergusson remarks, that it "displays the Pathan style at its period of greatest perfection when the Hindu masons had learned to fit their exquisite style of decoration to the forms of their foreign master." This gateway is in the south cloister of Ala-uddin's extension, a little beyond the line of that of Altamsh's and was probably the city gate of the mosque. The date of the building is given on the eastern, western, and southern doors of the gateway: "On the 15th day of Shavval, 710," (A.D. 1310.)
The building is a square of 34 ½ feet inside and 56 ½ feet outside, the wall being 11 feet thick; from the inner floor to the domed ceiling, it is about 47 feet high. The mode in which the square plan of the building is changed into and octagon which supports the dome, "is more simply elegant and appropriate," says Fergusson "that any other example I am acquainted with in India;" the corners are ornamented with a series of arched niches which cut off the angles of the square. On each side of the gate way there is a lofty door, but the doors in the eastern and western sides of the building are lower than those in its northern and southern sides. On the southern side the building has a plinth very nearly ten feet high, with seven steps in the centre leading into it.
The door ways are most elaborately ornamented; each door is formed by a pointed horse shoe arch, of which the outer edge is paneled; the inner edge, which goes a few inches deeper into the arch, is decorated with stone spear heads; the arch springs from slender ornamented pillars with plain imposts. The outer face of the arch, as well as the inner arch, which is formed after a recess of four inches, and the rectangular bands which enclose the arched doorways, bear inscriptions which in some places have been injured by time. The whole face of the building is elaborately ornamented with delicate chiseling of which not the least attractive features are the bands of inscription. On each side of the doorway there are two windows, about a third of its size but of the same shape and style; these windows are covered with marble screens of lattice work; the off windows are a little smaller than the near ones and their lattice work is closer and finer. Above these windows, the wall is decorated with small ornamental false arches in panels, which from a distance have the appearance of small windows in groups of fours, the two vertical arches of each group, being enclosed in oblong marble bands.
The rectangular bands of red sandstone and marble which enclose the arches of the windows, and the small false arches above them, are covered with verses from the Quran and the Hadis of Muhammad artistically engraved. The spandrel, as usual, is mass of fret work, wreaths and ornamental bosses in red sand stone. The upper portion of the southern face of the gate way was repaired by Major Smith, but no attempt was made to restore the stone ornaments. The interior walis of the gateway are profusely decorated with the most perfect specimens of elaborate carvings; the chequered pattern is simply elegant, or as Fergusson calls it, "of unrivalled excellence." The large dome is remarkably plain; Fergusson considers it "by no means worthy of the substructure," but its interior view is by no means disagreeable, its plainness notwithstanding; from outside, the dome looks rather low. The outer walls of the gateway were crowned with a battlemented parapet; that on the southern wall was removed during Major Smith's repairs.
In 1827 when Major Burt visited the gateway, he described it as in " a state of dilapidation and destruction" and prophesied that "none of it will stand;" two years later it was repaired by Major Smith, as already stated.