It has been seen that the portals of the Cathedral were kept open day and night for the convenience of the pilgrims; those who had been unable to receive shelter in the overcrowded inns often passed entire nights within the precincts of the Cathedral, sleeping on the stones of the cloister and even in the Cathedral itself, using the galleries as if the sacred edifice had been an inn. If we may trust Quintela Naya, it was not till the thirteenth century that the making up of beds in the Cathedral was forbidden. In order that the atmosphere of the edifice might be purified for the relays of pilgrims, recourse was had to incense-burning, and there eventually came into use, history cannot tell us when, the wonderful _botafumeiro_, or giant censer, which is to this very day one of the glories of the Cathedral. There seems to be no trace of the use of incense in Christian worship during the first three centuries. St. Clement of Alexandria (A.D. 192) said, when contrasting the Christian service with pagan rites, “the truly holy altar is the just soul, and its perfume is holy prayer.”[88] Only when great crowds of unwashed pilgrims began to make the air of the churches intolerable was the use of incense, as a disinfectant, introduced into Divine Service.[89] Its use as a part of the ritual dates from about the end of the fifth century. It is supposed that all the side chapels of Santiago Cathedral had at first their own incense-burners, but that when the pilgrims took to sleeping round the altar and in the gallery which encircles the nave and transept, these being found insufficient to purify the air of the entire building, their place was taken by a huge silver casket filled with incense and suspended by iron chains and by ropes and pulleys from the triangle of the cupola. This great _incensario_ was solemnly swung the whole length of the nave backwards and forwards above the heads of the pilgrims.