The Portuguese journeys around the West African coast opened up new avenues for trade between Europe and West Africa. By the early 16th century, European trading bases, the factories established on the coast since 1445, and trade with the wealthier Europeans became of prime importance to West Africa. North Africa had declined in both political and economic importance, while the Saharan crossing remained long and treacherous. However, the major blow to trans-Saharan trade was the Battle of Tondibi of 1591–92. Morocco sent troops across the Sahara and attacked Timbuktu, Gao and some other important trading centres, destroying buildings and property and exiling prominent citizens. This disruption to trade led to a dramatic decline in the importance of these cities and the resulting animosity reduced trade considerably.