Pietro Montani was born in Trieste but grew up in Istanbul’s Galata quarter. There is no information on his professional education. In sources he is described as an architect, a painter and above all as a decorator. He produced many measured drawings of monuments in Istanbul, which partly were lost in 1870 in one of Istanbul’s great fires. He produced many scale drawings of monuments in Istanbul, some of which were lost in 1870 in one of Istanbul’s great fires. Several drawings appeared in the 1873 publication on Ottoman architecture. The drawings demonstrate his technical skills when it comes to architectural representation. As a decorator he is claimed to have been involved in the Pertevniyal Valide Mosque in Aksaray and the Çırağan Palace in Istanbul. He was the architect of the Ottoman pavilions at the Vienna world's fair in 1873 (Ersoy, 2015, pp. 118–119).
Montani wrote the chapter on the technical principles of Ottoman architecture and presumably the part on decoration in Die Ottomanische Baukunst / L’Architecture ottomane / Uṣūl-i Miʿmāriyye-i ʿUsmaniyye (Ersoy, 2015, p. 107). He is furthermore the author of the publication L’harmonie des sphères from 1865. Also, he worked for two French journals as illustrator (L’Illustration; Le monde illustré). In 1877, he was appointed alongside Marie de Launay and Osman Hamdi Bey to the so-called Museum Commission which developed strategies and regulations concerning the archaeological activity in the Ottoman Empire. In 1878, he became the chief architect of Eastern Roumelia, a newly established semiautonomous province. (Ersoy, 2015, pp. 120–122)