How was islam able to cross the sahara desert in the eighth century?

Islam was spread across the Sahara Desert by a vast network of traders who had been trading Salt and Gold across the Sahara Desert for hundreds of years. The people of the region the "Berbers" from North Africa and the Saharan region were converted to Islam and subsequently helped to spread the religion across the region into West Africa through contacts with a wide variety of peoples and cultures along the way.