Giuseppe Simone Assemani was born on 27 July 1687 in Hasroun, Mount Lebanon into the Assemani family. His surname is related to several distinguished Orientalists and clergy. "Assemani" is an Arabic patronymic which means son of Simeon, but this did not prevent him from being called Simon. When very young, in 1703, he was sent to the Maronite College in Rome, and was transferred thence to the Vatican library. Assemani graduated in 1709. A talented graduate (at that time he had written three essays on the Syrian grammar and theology), he was spotted by Pope Clement XI, who kept him in Rome and ordered him to catalogue early Christian manuscripts that were brought in 1707 from Egypt by his brother Elias. In 1710, Giuseppe worked as scribe of Oriental manuscripts (scriptor Orientalis), translator from Arabic and Syriac languages, and advisor to the Congregation for the review and reform of the liturgical books of the Eastern rites. He was ordained priest on 21 September 1710. In 1711 Assemani received papal authorization to pass from the Maronite rite to the Latin rite. From 1715 to 1717 he was sent to Wadi El Natrun, Cairo, Damascus and Lebanon to search for valuable manuscripts, and returned with about 150, which formed a collection in the Vatican Library. In 1735 Pope Clement XII sent him again to the East where he presided the 1736 Maronite Synod of Mount-Lebanon, which laid the foundations for the modern Maronite Church. He returned with a still more valuable collection, because he found the opportunity to collect even more ancient works. This time he brought about 2,000 works, and the most important of them was the Codex Assemanius, an evangeliary which he had brought from Jerusalem in 1736. He later played a significant role in mediating several crises in the Maronite Church hierarchy, by virtue of his influence in Rome and his knowledge of the Maronite Church.