The power of the caliphs was now upon the wane: the disorders consequent upon the introduction of Turkish guards at Baghdád by El Mo‘tassem first weakened their authority; but the revolt of the Carmathians in 877, during the reign of El Mo‘tammed Billah, struck the first fatal blow against the House of Abbas. The sect of the Carmathians was founded by a certain Hamdán, surnamed Carmat. His doctrines consisted in allegorising the text of the Cor’án and the precepts of Islamism, and in substituting for their exterior observance other and fanciful duties. Carmat was an inhabitant of the neighbourhood of Basora, and his sect took its origin in that place, and soon spread over the whole of Irak and Syria. Under a chief, named Abu Táher, these fanatics defeated the Caliph el Moktader Billah, and held possession of the whole of the Syrian desert. With a force of more than a hundred and seven thousand men, Abu Táher took Rakka, Baalbekk, Basra, and Cufa, and even threatened the imperial city of Baghdád itself. The caliph made strenuous exertions to suppress the rebellion, but his soldiers were defeated, and his general taken captive and treated with the utmost indignities. A strange story is told of this struggle, which illustrates the fierce fanaticism and blind devotion of Abu Táher’s followers. A subordinate officer from the Mussulman army penetrated to the rebel camp, and warned the chief to betake himself to instant flight. “Tell your master,” was the reply, “that in all his thirty thousand troops he cannot boast three men like these.” As he spoke, he bade three of his followers to put themselves to death; and without a murmur, one stabbed himself to the heart, another drowned himself in the waters of the Tigris, and a third flung himself from a precipice and was dashed to pieces. Against such savages as these, the luxurious squadrons of Baghdád could do nothing—they were ignominiously defeated; and the Carmathians roamed whithersoever they pleased, and devastated the country with fire and sword. In 929 Mecca itself was pillaged, thirty thousand pilgrims slain, and the black stone, the special object of adoration to the true believer, was carried off. This circumstance caused another diversion in favour of Jerusalem; the Ka‘abah was again deserted, and crowds of devotees flocked from all parts of the Mohammedan world, to prostrate themselves before the Holy Rock of David. For the Christian inhabitants of Jerusalem the change was an unfortunate one: Mussulman bigotry was again in the ascendant in the Holy City, and we learn that in 937 the church of Constantine was destroyed, and the churches of Calvary and the Resurrection once more ruined and despoiled.