Pascal Sébah (1823-1886) was an Ottoman pioneer photographer who worked in Istanbul. He was born in Istanbul to a Syrian Catholic father and an Armenian mother. In 1857 he opened his first photography studio in Istanbul and by 1873 was successful enough to open another studio in Cairo. After he died in 1886, the studio was managed by his brother Cosmi until Pascal's son, Jean, joined him in 1888.
Read more about Pascal Sebah in "Between Orientalist Cliches and Images of Modernization" by Michelle Woodward and visit Luminous Lint Gallery to see more of his photographs.
Special thanks go out to Christoph Laubsch for sharing his knowledge during my research.
His collection of Pascal Sebah's photographs can be found on annaona.de.