For the next eight years, the Almohad revolt was largely confined to an irresolute guerilla war through the ravines and peaks of the Atlas range. The principal damage done by the Almohads at this stage was the disruption of Almoravid tax-collection, and rendering insecure (or altogether impassable) the roads and mountain passes south of Marrakesh. The Sous valley, surrounded on three sides by Almohadist Masmuda mountaineers, was nearly cut off and isolated. Of more particular concern to the Almoravids was their threat to the Ourika and Tizi n'Tichka passes, that connected Marrakesh to the Draa valley on the other side of the High Atlas. These were the principal routes to the all-important city of Sijilmassa, gateway of the trans-Saharan trade, by which gold came from west Africa to Morocco. But the Almoravids were unable to send enough manpower through the narrow passes to dislodge the Almohad rebels from their easily defended mountain strongpoints. The Almoravid authorities reconciled themselves to setting up strongpoints to confine them (most famously the fortress of Tasghimout that protected the approach to Aghmat), while exploring alternative routes through more easterly passes.