Construction of Istanbul’s Nur-u Osmaniye Complex Summary

  • Last updated on November 10, 2022

The last great work of Ottoman religious architecture, the Nur-u Osmaniye mosque complex assimilated European stylistic influences into the classical Ottoman style. Combining a mosque, school, and library, the complex has functioned since its completion as an important repository and purveyor of Islamic knowledge and faith.

Summary of Event

Construction of the Nur-u Osmaniye complex began in 1748, during the rule of Ottoman sultan Mahmud I, and was completed under the auspices of his brother and successor Osman III in 1755. Built to replace the mosque of Fatma Hatun, Fatma Hatun mosque, Istanbul which was destroyed in a fire, the complex was located to the east of Constantinople’s covered bazaar. Its name, meaning “light of Osman,” is thought to refer to Osman III and to a verse from the Qū՚ran’s Light Chapter, which is also inscribed inside the building’s dome: “God is the light of the heavens and the earth.” Though in keeping with the massing of Ottoman mosques and mosque complexes, or kulliye, Kulliye (mosque complexes) the structure also exemplifies the Baroque style Baroque;architecture of the eighteenth century and the Westernizing Westernization;Ottoman Empire vision of Mahmud I. [kw]Construction of Istanbul’s Nur-u Osmaniye Complex (1748-1755) [kw]Complex, Construction of Istanbul’s Nur-u Osmaniye (1748-1755) [kw]Osmaniye Complex, Construction of Istanbul’s Nur-u (1748-1755) [kw]Nur-u Osmaniye Complex, Construction of Istanbul’s (1748-1755) [kw]Istanbul’s Nur-u Osmaniye Complex, Construction of (1748-1755) Nur-u Osmaniye, Istanbul[Nuru Osmaniye] Ottoman architecture Architecture;Ottoman [g]Ottoman Empire;1748-1755: Construction of Istanbul’s Nur-u Osmaniye Complex[1260] [c]Architecture;1748-1755: Construction of Istanbul’s Nur-u Osmaniye Complex[1260] [c]Religion and theology;1748-1755: Construction of Istanbul’s Nur-u Osmaniye Complex[1260] Kalfa, Simeon Ahmed Efendi Mahmud I Osman III Yedikuleli Seyyid Abdullah Efendi Mehmed Rasim Yahya Fahreddin K{amacr}tipz{amacr}de Mehmed Ref{inodot} Efendi

The basic form of the classical Ottoman mosque was developed as early as the fourteenth century, from the simple cubic masses of cut stone that defined small structures such as the Haji Ozbek mosque at Iznik (1333). The prototypical plan consisted of a portico and domed prayer hall, and the interior functions of the mosque were visible from outside the structure. In keeping with such models, the mosque at the Nur-u Osmaniye complex consists of a single domed prayer hall, preceded by a courtyard of comparable size on the northwest. A main portal on the northwest opens onto the courtyard, the unique shape of which is composed of wedge-shaped segments set between nine domed bays. Light is drawn into the space by windows placed at two levels, each of which allows views outside the structure. A five-bay portico completes the courtyard and leads into the prayer hall through an axial portal.

The mosque’s prayer hall is square in shape, with a semicircular mihrab niche, which offers the direction of prayer. The interior space is capped by a dome that measures twenty-five meters in diameter and reaches a height of more than forty-three meters. The grand crowning element is set on four monumental arches surrounded by wide galleries on three sides. Below the galleries sits an exterior arcade accessed through two side doors with steps. In three places, balconies project into the prayer hall on columns. The one to the east, which served as a space for the sultan, has gilded latticework between its columns and was accessible on horseback by way of a ramp outside the mosque. Windows at the base of the dome and sixteen windows in each of the tympana of the grand arches bring light into the domed space, where they add to the illumination provided by numerous casement windows at the ground and gallery levels.

In keeping with the classical function of the Ottoman kulliye, the site consists of a mosque, medrese (theological college), soup kitchen, tomb, library, and water fountain. At the Nur-u Osmaniye complex, these functional units are contained within a walled precinct of irregular shape, while stores were built outside in close proximity to the complex. The medrese, built on a traditional arcaded plan, consists of twenty domed rooms and a large classroom surrounding a courtyard. The soup kitchen adjoins the medrese to the west and is entered through a domed structure to the north. The complex’s single-story library is set on a high platform accessed by two sets of stairs to the west. An Arabic inscription above the dual entrance hints at the structure’s function: “Demand science, from the cradle to the grave.” Its space consists of a domed elliptical reading room with rounded corners, surrounded by an arcade of fourteen columns.

The decoration of the complex deviates significantly from earlier examples of Ottoman architecture, incorporating Baroque ornamentation derivative of Western European styles. The interior of the mosque is covered with gray marble panels and a thick structural cornice, and below the gallery level, calligraphic medallions crown each casement window. Baroque influences are seen in the extensive use of decorative sculptural elements such as pilasters and cornices, and in the addition of contemporary Western motifs such as garlands, finials, and scallops. On the structure’s exterior, as well, the domed silhouette of the Ottoman mosque is defined with the curved outlines of Baroque buttresses anchoring the dome at its corners. The site’s unique synthesis of classical Ottoman and contemporary Western styles is witnessed most clearly in the scalloped stalactite domes that crown the mosque’s portals and bronze window grilles. Originally gilded, the intertwining grille patterns are particularly elaborate—a trend that would continue in Ottoman architecture in the second half of the eighteenth century.

By the mid-fifteenth century, Ottoman architects had begun to gain recognition, as individual builders developed new ideas that exceeded the well-established formulas that had previously guided stone masons. Little is known about the architect of the Nur-u Osmaniye, who has been identified as Simeon Kalfa. The likelihood of significant contributions by a European are evident in the building’s Westernized forms, and such contributions would befit the eighteenth century, when Ottoman envoys were sent to European courts and returned with descriptions of Western arts. The eighteenth century was also the beginning of a period in which non-Muslims were commissioned to build important royal structures, including mosques, and artists and architects were invited to the Ottoman court from Europe.

Despite the paucity of evidence about the architect’s life, the construction itself was documented in detail by the construction manager, Ahmed Efendi, in a book titled Tarih-i Cami-i Serif-i Nur-i Osmani (mid-eighteenth century). Moreover, a considerable amount is known about the calligraphers responsible for inscriptions on the Nur-u Osmaniye. Mehmed Rasim, the outstanding Ottoman calligrapher of the first half of the eighteenth century, penned the Qū՚ranic verse on the mosque’s middle gate, facing out, and devised the chronogram for its construction, which read, “May this new congregational mosque of Sultan Osman be blessed!” The calligrapher Yahya Fahreddin composed the verses inside the mosque’s two side gates, and Ḥākim Efendi composed the chronogram of the medrese: “Ḥākim composed a chronogram in the form of a prayer; May the gate of the medrese be the door to knowledge.” Finally, two of the most accomplished calligraphers of the eighteenth century, Yedikuleli Seyyid Abdullah Efendi and Kātipzāde Mehmed Refı Efendi, contributed verses to the structure.


The inherently rich detail of Islamic architectural traditions was well suited to the Baroque influences that came into the Ottoman Empire in the early eighteenth century. The last great work of Ottoman religious architecture, the Nur-u Osmaniye mosque, assimilated these contemporary European stylistic flourishes, while maintaining the traditional features and floor plan of classical Ottoman mosques. The site preserves the legacies of sultans Mahmud I and Osman III. A tomb at the site, originally intended for Mahmud, houses the remains of Sehsuvar Valide Sultan, mother of Osman III, and the Nur-u Osmaniye library, opened in 1755, still functions as a repository for the personal manuscript collections of both rulers, a repository with more than five thousand volumes.

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Blair, Sheila S., and Jonathan Bloom. The Art and Architecture of Islam, 1250-1800. New Haven, Conn.: Yale University Press, 1994.
  • citation-type="booksimple"

    xlink:type="simple">Bloom, Jonathan, and Sheila Blair. Islamic Arts. London: Phaidon Press, 1997. Two important works by leading scholars of Islamic art and architecture.
  • citation-type="booksimple"

    xlink:type="simple">Crane, Howard. The Garden of the Mosques: Hafiz Huseyin al-Ayvansarayi’s Guide to the Muslim Monuments of Ottoman Istanbul. New York: Brill, 2000. Translation of a rare contemporary source on Ottoman architecture. Annotated with a glossary and bibliography.
  • citation-type="booksimple"

    xlink:type="simple">Goodwin, Godfrey. A History of Ottoman Architecture. London, 1971. A concise survey of architecture’s development and form under the Ottoman sultans.
  • citation-type="booksimple"

    xlink:type="simple">Kuran, Aptullah. The Mosque in Early Ottoman Architecture. Chicago: University of Chicago Press, 1968. Provides a background to later developments in Ottoman building, with illustrations and plans.
  • citation-type="booksimple"

    xlink:type="simple">Necipoglu, Gulru. “Anatolia and the Ottoman Legacy.” In The Mosque: History, Architectural Development, and Regional Diversity, edited by Martin Frishman and Hasan-Uddin Khan. New York: Thames and Hudson, 1994. Concise chapter, assimilating updated research on the development of Islamic architecture in Anatolia. Illustrated.
  • citation-type="booksimple"

    xlink:type="simple">Unsal, Behcet. Turkish-Islamic Architecture in Seljuk and Ottoman Times, 1071-1923. New York: St. Martin’s Press, 1973. A fine survey of Turkish building types, beginning with early Islamic buildings. Contains plates, illustrations, and maps.

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