Sarjun ibn Mansur (Arabic: سرجون بن منصور Greek: Σέργιος ὁ τοῦ Μανσοῦρ) was a Melkite Christian official of the early Umayyad Caliphate. The son of a prominent Byzantine official of Damascus, he was a favourite of the early Umayyad caliphs Mu'awiya I and Yazid I, and served as the head of the fiscal administration for Syria from the mid-7th century until the year 700, when Caliph Abd al-Malik ibn Marwan dismissed him as part of his efforts to arabize the administration of the Caliphate.
He was the father of the theologian John of Damascus and adoptive father of Cosmas of Maiuma.[1]