66 A TROPICAL DEPENDENCY and its surrounding provinces, and fixed their capital at Fez. When nothing was left to the Almohades but Tafilet and a small part of Ifrikiah, they returned to their stronghold of Tinmelel, to maintain for a few years only a *' phantom Caliph," Ishak, last of his race, who, when the successful siege of Tafilet in 1274 had given all that remained of Moroccan soil to the Merinites, was brought before the ruling sovereign of that dynasty and executed. It is interesting to note that at this siege of Tafilet, which put an end to even such empty pretence as still remained of the Dual Empire of Spain and Africa, mention is made of the use of firearms, or *' fire-engines," which threw out iron gravel. The shot, it is said, was forced from the piece by means of a burning powder, ''of which the singular properties work effects that rival the power of the Creator."