They had this sentiment and inspiration common to them all--their fighting religion; but the caliphs of Mahomet never showed any of that power of organisation, any of that capacity for governing a great empire from a single centre, which had been so remarkable in the Romans during the first hundred years or so after the birth of Christ. The capital, or chief place of residence of the caliphs, became, after a while, Bagdad, on the Euphrates. It was more central and convenient, no doubt, than a city in the Arabian desert. But, first of all, the ruler of the {75} African province tried to assert himself as independent of the caliph; then the ruler of Spain, more distant still from the centre, claimed independence more strongly and successfully; and so it was also with other provinces in the circumference of the wide and constantly widening Empire. The links, as we say, of the Empire chain were not very solid or strong. But there was always this in common, to help keep all together--their religion. If the caliph in Bagdad had little or no control over the doings of the Moorish ruler of Spain, if the latter made war and peace and so on as seemed good to him without referring for orders to headquarters, the caliph still had some influence over him and his followers in religious matters, as being the representative and successor of Mahomet, who was Allah's prophet. It was very like the power which the Roman Church, with the Pope at its head, had over the Christians. The Roman Empire, in a military sense, and in the sense of having Rome as the centre of its government and laws, had gone to pieces. There was no more "appealing unto Cæsar," or to any authority at Rome, from the decision of a court of law in some far-off province--as St. Paul appealed at Cæsarea--but still the Pope had his far-reaching power. The officials of government had gone from the cities of Gaul or of Britain or wherever it might be; but the clergy remained, and grew more and more in number, and the authority of the Pope of Rome--or even of the Pope from Avignon or Ravenna, for sometimes, as we shall see, he was obliged to fly from Rome--had its power over these clergy and through them over the laity. Ever since Constantine had made Christianity the State religion they had been servants and officials, in this manner, of the dying Empire and of the growing Church. The caliph's power was a like power, because he was the successor of Mahomet, though it {76} was never, in its spiritual influence, of equal power with that of the successor of St. Peter. But the two may be compared, and the comparison is very interesting. [Sidenote: Charlemagne]