non-Moslems must retain their lands, cultivate them and pay the land-tax (the Arabic word is also used of revenue from the work of a slave) and the poll-tax (the Arabic word means also "ransom"), and give contributions in kind to support the local Moslem garrisons which were massed in great camp-cities at strategic points. If a non-Moslem embraced Islam he entered the ruling caste; his land was distributed among his non-Moslem fellows, and he no longer paid the land-tax but rather received support from the public funds. The amount of these pensions varied with the standing of the pensioner from 10,000 dirhems (a dirhem equalled about a franc) to the widows and relations of the Prophet down to 300. This bureau had, therefore, not only to keep the books of the state, but also to maintain a list of all Moslems, classified genealogically and socially. Its registers were kept by Greeks, Copts and Persians; the Arabs, it may be said in general, adopted the method of administration which they found in the captured countries and drew upon the trained services of their inhabitants. Such a system led naturally to wholesale conversions to Islam; and the consequent decline in revenue, combined with large donations of lands by Othman, the third caliph, to his own family, gradually broke it down. The first patriarchal period of conquest, unearned wealth and the simple life--called by Moslems the period of the "four rightly guided caliphs," and very happily by Sachau, _ein mönchisches Imperium_--passed rapidly into the genuinely Arab empire of the Omayyads, with whom came an immediate development of organization in the state. The constructive genius in this was Moawiya, the first Omayyad caliph. Under him the old simplicity vanished. A splendid and ceremonious court was maintained at Damascus. A chamberlain kept the door; a bodyguard surrounded the caliph, and even in the mosque the caliph, warned by the murder of Othman and of Ali, prayed in a railed-off enclosure. The beginning of the seclusion of the caliph had come, and he no longer walked familiarly among his fellow Moslems. This seclusion increased still further when the administration of the state passed by delegation into other hands, and the caliph himself became a sacrosanct figure-head, as in the case of the later Abbasids; when theories of semi-divine nature and of theocratic rule appeared, as in the case of the Fatimites; and finally when all the elaborate court ritual of Byzantium was inherited by the Ottoman sultans.