1790, particularly in Galicia, the peasants of ecclesiastical lands still constituted 10.5 per cent. of the entire population of the country at that time, or one-sixth of the peasantry alone.[327] At that time, besides their lands, the clergy owned also over one-tenth of the houses in Poland, or 153,551 out of a total number of 1,434,919.[328] Moreover, in addition to these large estates and the income derived from them, the Polish clergy were entitled to one-tenth of the gross receipts which the nobility derived from their estates, to one-tenth from the peasantry, jura stolae, free gifts of the pious, and, as a specially privileged class, to exemption from practically all public burdens, although the Greek Orthodox clergy were placed on the same footing with the peasants as regards taxation.[329] The tithes paid to the clergy by the nobility were voluntary at first, but by the middle of the fifteenth century they were made compulsory;[330] and in consequence became very obnoxious to the nobility, for they were the only tax the nobility paid.[331] Before the thirteenth century the prince called upon the population of ecclesiastical estates as well as on that of the estates of the knighthood to participate in the building of new or in the rebuilding of old strongholds, but in the course of the thirteenth and fourteenth centuries, owing to the immunities granted the clergy, the princely right to summon the population of ecclesiastical estates to perform any work on defenses was either very much curtailed or altogether abolished.[332] Also, the mayors of ecclesiastical villages were largely exempt from participation in the country’s defense prior to the reign of Casimir the Great (1333-1370). In Casimir’s time a law was passed, making these mayors liable to military service.[333] The clergy, however, disregarded and evaded the provisions of this law after Casimir’s death. It was not until in the second half of the sixteenth century that the nobility brought the clergy to terms in this regard. Taking their actual receipts plus the value of their exemptions into account, Dr. Kubala estimates that the Polish clergy of the sixteenth century were recipients of one-half of the national income.[334]