Jawhar ibn Abdallah, surnamed Ja'far al-Siqilli ("the Sicilian"), al-Rumi ("the Byzantine"), al-Saqlabi ("the Slav"), al-Katib ("the Chancellor") and al-Qaid ("the General"), (, born early 10th century, died 992), was the most important military leader in Fatimid history. He led the conquest of North Africa and then of Egypt, founded the city of Cairo and the great al-Azhar Mosque.