I have been referring to the decline, as I before spoke of the progress, of the Romans: the career of that people through twelve centuries is a drama of sustained interest and equable and majestic evolution; it has given scope for the most ingenious researches into its internal history. There one age is the parent of another; the elements and principles of its political system are brought out into a variety of powers with mutual relations; external events act and react with domestic affairs; manners and views change; excess of prosperity becomes the omen of misfortune to come; till in the words of the poet, "_Suis et ipsa Roma viribus ruit_." For how many philosophical histories has Greece afforded opportunity! while the constitutional history of England, as far as it has hitherto gone, is a recognized subject-matter of scientific and professional teaching. The case is the same with the history of the medieval Italian cities, of the medieval Church, and of the Saracenic empire. As regards the last of these instances, I am not alluding merely to the civil contentions and wars which took place in it, for such may equally happen to a barbarian state. Cupidity and ambition are inherent in the nature of man; the Gauls and British, the tribes of Scythia, the Seljukian Turks, consisted each of a number of mutually hostile communities or kingdoms. What is relevant to my purpose in the history of the Saracens is, that their quarrels often had an intellectual basis, and arose out of their religion. The white, the green, and the black factions, who severally reigned at Cordova, Cairo, and Bagdad, excommunicated each other, and claimed severally to be the successors of Mahomet. Then came the fanatical innovation of the Carmathians, who pretended to a divine mission to complete the religion of Mahomet, as Mahomet had completed Christianity.[77] They relaxed the duties of ablution, fasting, and pilgrimage; admitted the use of wine, and protested against the worldly pomp of the Caliphs. They spread their tents along the coast of the Persian Gulf, and in no long time were able to bring an army of 100,000 men into the field. Ultimately they took up their residence on the borders of Assyria, Syria, and Egypt. As time went on, and the power of the Caliphs was still further reduced, religious contention broke out in Bagdad itself, between the rigid and the lax parties, and the followers of the Abbassides and of Ali.