By the fourth century it was believed that the blessed martyrs, through communion with our Lord, shared in his attributes of omnipresence and omniscience. Prayers in behalf of the saints changed to prayers to them for help. This transition was particularly easy for those who were won from paganism because they were already accustomed to similar practices. A festival of All Saints was instituted by Pope Boniface IV. in 610, when the Pantheon was dedicated as a Christian church, though it was not commonly observed until the ninth century, when Louis the Pious made it general in the Empire. The festival of All Souls supplemented it in the tenth century and became very popular. Every day in the calendar was dedicated to one saint or more. Down to the tenth century individuals renowned for some pious deed or for some suffering on account of the Christian faith were exalted to sainthood by the voice of the people with the consent of the bishop. Later, however, the bishops nominated the saints and the Pope conferred the honour. The first instance of papal canonisation was that of Ulrich, the Bishop of Augsburg, by John XV. in 973. Pope Alexander III. (1170), in the period when the Papacy was becoming all-powerful, seized this great prerogative into his own hands.[379:1] Each nation, district, city, and individual church had its saint. The fame of the saints was perpetuated by legend, hymn, painting, sculpture, and the sacred edifices built to their memory and honour. Consequently the tales and beliefs connected with the saints produced most of the literature of the Middle Ages--the poetry, the song, the history, and the subject of common thought, conversation, and feeling.