(r. 1549–1582), asking the latter to pay him the equivalent of the tax revenues generated from the mines. In 1583 Al-Mansur's forces successfully occupied the Touat and the Gourara oases. In 1589 or early 1590 he then asked Askia Ishaq II to pay him an amount of gold proportional to the amount of salt taken from the mines, which Ishaq II contemptuously refused. The Saadian military expedition, composed of about 20,000 men, left Marrakesh on October 16, 1590, and reached the Niger River in February 1591. It was led by Judar Pasha, a commander of Spanish origin. The Saadian army suffered while crossing the desert, but Askia Ishaq II was surprised when they arrived and had to assemble his forces quickly. While the Songhai army was reportedly larger, it lacked firearms, unlike the Moroccans. At the Battle of Tondibi the Saadian army thus won a decisive victory. The Songhai evacuated their capital, Gao, and retreated south, while Judar Pasha's army occupied Gao along with Timbuktu (both in present-day Mali). After this victory, however, the Moroccans struggled to have their authority accepted in the region and continued to wage a protracted war with the remnants of the defeated Songhai Empire. In the end, Moroccan control was tenuously established over a large region stretching between Kukiya (also spelled Koukya or Koukiya) and Djenné, around the northern curve of the Niger River. Dissension continued to undermine the Moroccan occupation afterwards but around the same time Nuhu was himself overthrown (in 1599) and the Dendi Kingdom fell into disorder for several years. While Saadian control of the region did not last long after Ahmad al-Mansur's death, the conquered region nonetheless sent a caravan of riches and supplies to Marrakesh every year during this period. It provided Al-Mansur's realm with abundant gold, slaves, and ivory, as well as exotic animals such as elephants for the first time. Saadian gold nonetheless had difficulty competing with the abundant high-quality gold shipped from the Spanish colonies in the Americas, and the caravans themselves were costly. A part of their function was to provide an impressive display to the inhabitants of Marrakesh and to the sultan's guests every year. Decline Succession war (1603–1627) Al-Mansur's final years were marked by growing rivalries between his sons and by the plague, which arrived from Spain in 1597 and wrought severe destruction. Ahmad al-Mansur died of the plague himself on August 25, 1603.