Dakhil Darwaza literally an entrance gate, (Ar. dakhil, Per. darwaza), is the largest structure of its kind in the architectural history of Sultanate Bengal. It was the main entrance to the citadel of lakhnauti, the Muslim name of gaur (per. Gawr). The gateway was the most solid and most elegant entrance portal ever erected in Bengal.
The suggestion that it was erected by Sultan nasiruddin mahmud shah (1435-59 AD) at the time of the building of his citadel seems untenable. When the gateway of gunmant mosque, the city congressional mosque of the time of the restored Iliyas Shahis, could not be built to ensure that it could be reasonably time-enduring, how could such a strong and balanced structure like the Dakhil Darwaza be built at that timeFoodgrain We do not have a similar example even in pandua where the largest congressional mosque in Bengal was erected by the second Iliyas Shahi ruler, who is widely acknowledged to be the first great builder amongst the independent rulers of Bengal. The architecture of the gateway is an impressive one, and such an impressing structure could be built only when architecture has attained its full fruition. On this ground, it may be suggested that the Dakhil Darwaza was built in the Husain Shahi period. Antorio de Britto, the Portuguese interpreter (1521 AD), speaks of 'a mosque round the corner in front of Dakhil Darwaza'.
Hence the probability is that Alauddin husain shah, who was also the builder of the bara sona mosque, built the present gateway. The majesty of both the architectural pieces bring them at par in point of time. It is likely that the present gateway was s substitution of a weaker gateway built by Nasiruddin Mahmud Shah at the time of the erection of the citadel. Because of their weak construction similar inner gateways named Chand Darwaza and Nim Darwaza had vanished.
The gateway built of bricks except the piers between the doorways, which are faced with stone up to the springing of the arches, measures 102.5m by 22.5m and consists of a passage 4.5m wide through the middle of the structure. On both sides of the corridor are two guardrooms entered from the former through subsidiary entrances numbering four on each side. The guardrooms measure 22.70m by 2.90m and have also two exits leading outside. The height of the gateway, measured by Cunningham, was about 14.95m of which the entrance arch rises to a height of 10.35m. Behind the wider arch is a smaller archway through which the entrance is made to the vaulted passage. The gateway arch projected in the form of an iwan portal, which is flanked on either side by massive twelve-sided towers at the corners, which are in perfect harmony with the design, and speaks of a gateway commensurable to the dignity and prestige of a great ruler. By a comparison with the entrance gateways of the Bara Sona and chhota sona mosque it can be surmised reasonably that the cornice of the portal was curvilinear.
The decoration of the gateway was not profuse. The ornaments, all in terracotta like other monuments of the time, consisted of string mouldings, at base levels, inset fret-rings around the corner towers - all segmented with vertical offsets, window-shaped arched-panels with hanging motifs inside and rosettes on the spandrels of arches. The arched window motif above the inner arch and flanking the outer arch on both sides are some of the traditional but beautiful examples of Sultanate ornaments stylized from the adina mosque at Pandua-Firuzabad. The Dakhil Dawraza must have been the grandest and the most majestic of all the monuments of Gaur-Lakhnauti. [ABM Husain]