The Banu Najjar (Arabic: بنو نجّار) were a Muslim, Christian and Druze tribes who lived in Medina in the time of Muhammad. They are one of the tribes named in his Charter of Medina.
The Banu Najjar were also the maternal tribe of Muhammad's grandfather Abdul-Muttalib. Muhammad initially settled with them when he emigrated from Mecca to Medina. The Prophet's Mosque was later built in the same location. During this period, most of the tribe converted to Islam.
References
Banu Najjar Wikipedia(Text) CC BY-SA