It is supposed that the collection of the tithe has its origin in Mosaic Law. In Christian times, from being a voluntary payment, it became a permanent tax, and it persisted throughout the Middle Ages. In it is to be found one of the origins of taxes on movables and, according to some economists, of general property taxes. The keynote to a proper understanding of the transition to secular taxation is found in the Saladin Tithe. As a source of Church revenue the tithe was of great importance, and since the Church exercised many of the functions now assumed by the state, it is conceivable that it should be regarded as a tax from the time when compulsion was first introduced into the collection of it.
It is well known that tithes were levied from the earliest times in the Christian era, and Pope Gregory I made a division of the proceeds of the tithe among the following: (a) the bishop, (b) the parish clergy, (c) church fabric, (d) the poor. By the Fourth Council of Toledo, however, the tithe, which had been appropriated by the lower clergy, was put under the special care of the bishops, who supervised its proper distribution. It was only one of the three sources of income which the clergy enjoyed in the seventh century.
Source: Mansi J. D., Sacrorum Conciliorum Nova et Ampissima Collectio, Vol. X, p. 628 ( H. Welter, Paris, 1901). -- A.D. 6 33).
33. Avarice is the root of all evil, and its thirst grips even the minds of the priests. Many of the faithful, out of love for Christ and the martyrs, construct churches in the parishes of the bishops, and gather offerings which are taken by the priests and appropriated by them for their own use. Hence it is that worshipers of things holy become disheartened at the loss of their funds. Hence also the ruins of tottering churches are not repaired because all the money