Mosques and Single-domed Mosques
One can classify the mosques located in the province of Bursa according to their design, from the simplest to the most evolved, thus:
Mosques with Framework Roofs: Though the majority of Istanbul mosques utilize walls of dressed stone and double-hip roof designs, the mosques in Bursa exhibit a preference for the single dome on square plan. Modest neighborhood mosques in the city also present walls of rubble stone in alternating courses or half-timbered with courses of sundried bricks and coverings of double-hip roofs.
The origins of this scheme, which is typically employed for small mosques designed on a neighborhood scale, but, occasionally, for larger mosques-as with the Green mosque at İznik-can be sought in Seljuk-style mosques. Intended at first for small mosques, the design is today used for almost all mosque structures. In later periods, a minber or raised pulpit was added, and by enlarging the scope of deeds of trust for pious foundations, they were eventually transformed into larger Friday mosques. These structures are on the square plan by a domed sanctuary and present, at the portal, a portico set off by an arcade; the minaret is placed either on the east or west wall, at the point demarcating the two sections. The transition to the dome is achieved by a band of prismatic triangles, pendentives or squinches.
The oldest example of this kind of mosque is the Alâaddin Bey mosque, erected in the Hisar (citadel) area in the year Bursa was captured (1326). The pointed arches of brick in the portico arcade are seated on re-used column capitals, the earliest example of its kind in the Ottoman period. Most notably, in the second half of the fifteenth century, a type of small mosque emerges that is peculiar to Bursa, whose examples closely resemble each other. On a square plan and domed, the common features of these structures is that they are in three units and present an enclosed portico with a gable wall ornamented by a geometric pattern of brick and stone. Two examples that we may note are the Sittî Hatun mosque and the Tuzpazarı mosque from the reign of Sultan Mehmed II (1421-81).
On the east side of Bursa, the Emir Sultan mosque and complex, situated on a site overlooking the city, contains the tomb of Muhammed Şemseddin Buharî (d. 1429), who was known as Emir Sultan and who immigrated from Buhara to Bursa where he settled in 1391 during the reign of Beyazıd I. Emir Sultan was a scholar of the age and a dervish of Kübreviyye lodge, a branch of the Nurbahşiyye order. The mosque forming the center of this architectural group, which was a prominent dervish cloister of the day, was constructed by Hundî Fatma Hatun, who was the daughter of Beyazıd I as well as the wife of Emir Sultan. The mosque was demolished in the earthquake of 1795-96 and was wholly re-built by Selim II in 1804-05. The sanctuary of the structure, which is the largest of the single-domed mosques in Bursa, is covered by a dome on a circular drum with squinches. The wall piers that support the squinched vaults and the facades are enlivened by cut-stone courses on the lower portion and alternating courses of stone and brick on the upper portion; the arches on the axes of these facades, which carry upward from the line of the eaves just as in Byzantine structures, suggest that Greek apprentices were employed in the construction of the mosque. The square bases on which stand the cylindrical minarets of courses of dressed stone at the northwest and northeast corners of the sanctuary, which is illuminated by some fifty windows, rise to the upper level of the carrying walls. The rectangular ablution fountain set crosswise in the courtyard enclosed by an arcade of ogee arches and cloistered vaults, which are both plastered in the lathe and plaster bağdadi technique, was built by Abdülaziz between 1868 and 1869. On the north side of the courtyard, on the mihrap (niche oriented to Mecca) axis, stands the tomb of Emir Sultan, which was restored in the same year.