Under the last Carlovingians the liturgy gradually deteriorated; less in the East perhaps than in the West, less at Rome and Milan perhaps than elsewhere, but everywhere the signs of deplorable relaxation and falling away were manifest. The choristers attempted to assume the privileges of the clerks; the deacons arrogated to themselves impossible rights of independence; the priests despised the bishops, and too frequently the bishops, presuming on their power, had the audacity to disobey the pontifical decrees. This change and deterioration principally showed itself in the psalmody, in the chants, in the adornment of the sanctuary, and in the dress of the ecclesiastics. The Byzantine methods of treatment, as applied to architectural monuments and to the various forms of Christian art, did something to preserve the traditions of the liturgy, but from the close of the tenth century till the twelfth much confusion prevailed in the Latin Church. It was reserved for the Crusades, after a century and a half of adventurous expeditions, to bring back from countries beyond the sea, from Antioch, from Constantinople, and from Jerusalem, the elements and the principles of a Neo-Greek liturgy, in which the degenerate Gallo-Roman was as it were saturated, and its whole character remodelled. The Catholic liturgy thus underwent a touching and marvellous transformation; this transformation was inaugurated by the construction of new churches, in which the Romanesque style gave place to that of the Ogive or Gothic; by the erection of slender belfries, recalling the minarets of the Mahometan mosques; by the introduction of transparent pictures on painted glass; by the chaste but splendid appointments of the chapels; by the dazzling decorations of the altars; by the melody of the church bells, the sonorous messengers of religion calling the faithful to prayer; and by the harmony of the human voice with the organ and other musical instruments. A complete and ingenious symbolism was contained in this comprehensive allegorical ritual, and rendered the liturgy a veritable sanctuary of Christian instruction and sacred tradition, each mystery (Fig. 188), each precept of which penetrated into the soul, as it were, through the medium of the senses.