An Arabian tribe who, on the first spread of Islam, were occupying a province in Mesopotamia, and professing the Christian faith.. The Banu Taghlib sent an embassy to Muhammad, formed of sixteen men, some Muslims and some Christians. The latter wore crosses of gold. The Prophet made terms with the Christians, stipulating that they should themselves continue in the profession of their religion, but should not baptize their children into Christian faith. (Sir W. Muir, from Katibu ‘l-Waqidi, p. 61.
Based on Hughes, Dictionary of Islam