Leone Caetani (September 12, 1869 – December 25, 1935), Duke of Sermoneta (also known as Prince Caetani), was an Italian scholar, politician and historian of the Middle East.
Caetani is considered a pioneer and founding father in the application of the Historical method on the sources of the early Islamic traditions which he subjected to minute historical and psychological analysis.
He emigrated to Canada in 1927 with Ofelia Fabiani. They brought with them their daughter Sveva, who after an appalling childhood emerged as a highly talented painter.
Caetani was born in Rome into the prominent and wealthy Caetani family. His father Onorato, Prince of Teano and Duke of Sermoneta, was Minister of Foreign Affairs in Italy in 1896 in the second di Rudini cabinet; his English mother, Ada Bootle Wilbraham, was the daughter of the Earl of Lathom. His paternal grandfather, Michelangelo, had married the Polish countess Calixta Rzewuski, whose ancestor Wacław Seweryn Rzewuski had been a well-known Polish orientalist.
Caetani developed an interest in foreign languages at an early age. At 15 he began to study Sanskrit and Arabic on his own. Later he studied Oriental languages at the University of Rome, under Ignazio Guidi and Giacomo Lignana, with an intensive study of Arabic, Hebrew, Persian, Sanskrit and Syriac languages (and perhaps also Turkish). Caetani spent many years researching and travelling throughout the Muslim world gathering a great deal of material on a wide range of Islamic cultures from Tunisia, Algeria, Egypt, Syria, Turkey, Iraq, the Levant, the Sahara, India, Central Asia and southern Russia. Later, one of his disciples was Giorgio Levi Della Vida. He had become a corresponding member of the Accademia Nazionale dei Lincei in 1911 and a full member in 1919. Later on, he left his rich library to the Lincei to create the Caetani foundation for Muslim studies.