Gaspare (1809-1883) and Giuseppe (1822-1891) Fossati were born in Ticino, Switzerland. They finished primary and middle school in Venice and studied architecture at the Brera Academy in Milano. After graduation from the Academy, Gaspare researched Roman and Renaissance buildings until 1833. He participated in the Pesto, Ercolano and Pompeii excavation works. In 1833, Gaspare went to Russia and joined the colony of Italian artists there. For a short while, he became famous and had many projects and commissions. At the end of 1836, he received the title of “court architect” in St. Petersburg and was appointed to Istanbul for the project of building in the Russian Embassy. During his stay in Istanbul, Gaspare worked with many Italian and local artists’ teams, including with his brother Giuseppe Fossati. The Fossati brothers completed more than 50 projects during the Tanzimat reform era in Turkey. Between 1841 and 1843, the Fossati brothers built the brick Bab-ı Seraskeri Hospital (Bekirağa Bölüğü) and Liman İskelesi Karakolu in Eminönü for the Ottoman Administration. As a result of the brothers’ success, they were formally appointed to renovate Arzuodası at Babıali in 1844, and to build important buildings in Sultanahmet such as Dârülfünun (university) (1845-1846), Hazine-i Evrak, and Mekteb-i Sanayi (1846-1848).

In 1847, Sultan Abdülmecid (1839-1861) appointed the Fossati brothers to renovate the Hagia Sophia. They completed the restoration in two years, utilizing more than eight hundred workers. They repaired the cracks in the domes and placed an iron chain around its base to support and strengthen it. The mosaics that had been covered during the reign of Sultan Mehmed II. were uncovered and repaired by order of the sultan. The Fossati brothers removed the Sultan’s lodge from the apse, and they built a new one against the pier to the north apse, with a gilded grille to conceal the Sultan. The new Sultan’s lodge was designed by Gaspare Fossati. He made the carved marble grille in the Turkish Rococo style and the columns in Byzantine style. The brothers also renovated the mihrab and the minbar. Their work on the Hagia Sophia was published in London as the album Aya Sophia of Constantinople as Recently Restored by order of H. M. The Sultan Abdulmedjid (1852). During their restoration work on the Hagia Sophia, they also added the entrance for the Sultan, Hünkar Mahfili (Sultan’s gallery), Kasr-ı Hümayun and the Muvakkithanesi (Clock Room). The Telgrafhane-i Amire building was built by Giussepe Fossati in 1855. Upon the death of Reşit Paşa in 1858, the Fossati brothers built his mausoleum in the corner of the graveyard in the Bayezit complex.

The Fossati brothers not only worked for Turks, but also for foreigners who resided in Istanbul. They built San Pietro Church in Galata between 1841 and 1843. They also renovated Venedik Palace (today the house of the Italian Ambassador) in 1853, and the Dutch Embassy in Beyoğlu in 1854. They built the Spanish (1854) and Iranian (1856) embassies in Istanbul. In addition, they built three Italian theaters. One of them was the Naum Theatre, which was built in Galatasaray in 1846. It was active until a fire destroyed it in 1870.

In addition to these buildings, the Fossati brothers also created many residences for Ottoman officers, such as Mustafa Reşit Paşa, Fuat Paşa, Ali Paşa, Ömer Paşa Hasib Paşa, Kamil Bey and Şevket Bey, and for Levantines, including Ottoni, Pedemonte, Spadaro, Srwdano Vagorides, Petrocochino, and Della Suda. Two of these houses, which were generally built in Pera and on the Bosphorus, are Reşit Paşa Palace (1847; today the Baltalimanı Osteopathic Hospital) and Hünkar Dairesi (1855; today the Social facility at Istanbul University)

In 1858, the Fossati brothers returned to their country, due to the reduced demand for new buildings, and the death of Reşit Paşa, who supported them. In Morcote, Switzerland, they built their own homes in the Turkish style. Gaspare moved to Milano in 1862. He designed the Duomo Square, and served as a jury member for applications for many works, including Galleria Vitoria Emmanuelle II, and Palazzo Marino. The Fossatis are buried in Morcote. In the Belizean Cantonal Archive in Switzerland, there are more than one thousand of their designs, layouts and other documents, which contain important information about Istanbul.

The Fossati brothers’ works in Istanbul:
Russian Embassy (1837)
Dârülfünun (1846)
Hazine-i Evrak Building (1846)
Hagia Sophia restoration (1847-49)
Bekir Ağa Bölüğü (1841-1843; currently the Faculty of Political Sciences at Istanbul University)
Reşid Paşa Palace (1847)
Lamartine (1850)
Hünkâr Dairesi (1855; currently the Social Facility at Istanbul University)