Laleli Mosque, which bears traces of the transition from classical Ottoman architecture to the baroque style on Istanbul’s historic peninsula, is regarded as the last imperial mosque complex commissioned by Ottoman sultans in the city.

Laleli Mosque is examined as an example reflecting the architectural transition from the classical Ottoman style to the baroque influence.

Commissioned by Sultan Mustafa III, the mosque was built between 1760 and 1764. Constructed by palace architect Mehmed Tahir Ağa, the structure is considered one of the notable works in Ottoman architecture where baroque influences became visible.

Laleli Mosque was designed not only as a place of worship but also as the center of a large külliye (complex). In addition to the mosque, the complex included structures such as a public soup kitchen, bazaar, shops, a madrassa, a sebil (public fountain), additional fountains, a tomb and a caravanserai.

Architecturally, the structure is regarded as one of the examples where the traditional Ottoman mosque plan was interpreted through a baroque style. The mosque’s central dome is supported by eight piers, while semi-domes and large windows give the interior a spacious and bright appearance.

The complex was located in close proximity to an important commercial district, and the shops belonging to the külliye played a significant role in generating revenue for the foundation that financed the mosque and its services.

Throughout history, the mosque has been affected by various disasters but has survived to the present day thanks to restorations carried out during different periods.

Academic and art historian Yasin Saygılı, who evaluated the mosque’s architecture, layout and decorative elements, said the structure represents a sultan’s complex built after the baroque style in Ottoman architecture became visible with the construction of Nuruosmaniye Mosque.

Saygılı emphasized that while the mosque reflects baroque influences, it also retains elements of classical Ottoman architecture.

He noted that Sultan Mustafa III was one of the rulers who played a major role in rebuilding Istanbul after the major earthquake and fires that damaged large parts of the city.

"After the Fatih Mosque built by Mehmed the Conqueror was destroyed, Sultan Mustafa III had it rebuilt, and many locations in and around Istanbul that had been destroyed or burned were reconstructed during his reign,” Saygılı said.

"He is also known for commissioning many mosques without giving them his own name. Structures such as Iskele Mosque, Ayazma Mosque and Laleli Mosque were all built during his period,” he added.

Saygılı pointed out that the Laleli Mosque reflects influences from both European and Eastern artistic traditions of the time.

"The S and C curves, the decoration of the dome, the use of stained glass windows behind the structure, the density of calligraphic works and inscriptions, and the gradual decline in the use of traditional tiles all demonstrate how Ottoman architecture was transitioning away from the classical style,” he said.

He also explained that the mosque was built primarily with cut stone, while in some sections the alternating masonry technique was used. Inside the mosque, a rich decorative program featuring marble panels was adopted.

Saygılı highlighted that the mosque’s location was also a commercial hub. "Because this area was a trade district, the lower level, or ground floor, was used as shops for commercial activities, while the mosque itself was constructed on a higher level above them,” he said.

"In a way, similar to the earlier Rüstem Pasha Mosque, the ground area was used for commerce to generate income for the foundation. At the same time, elevating the mosque provided a more monumental and spiritual appearance.”

According to Saygılı, the Laleli Mosque represents a transitional point in Ottoman architectural development before later examples such as the Pertevniyal Valide Sultan Mosque.

"With its sebils, commercial buildings and madrassa, Laleli Mosque became the last külliye commissioned by an Ottoman sultan,” he said.

"Later sultans continued to build mosques, such as the Mecidiye mosques, Yıldız Mosque and mosques commissioned by valide sultans, but after this period, rulers no longer constructed large mosque complexes that included multiple structures like madrassas, sebils and tombs.”

"For that reason, the Laleli Complex, built by Mehmed Tahir Ağa and commissioned by Sultan Mustafa III, can be considered the last imperial complex built by an Ottoman sultan in Istanbul,” he concluded.