The former, as more spiritual and impalpable, remained an article of faith, deep and fervent, only represented to the senses by the mystic masterpieces of Murillo. Transubstantiation, on the other hand, was embodied in a host of symbols and ceremonies, and had devoted to it the most gorgeous of all the festivals of the church--that of Corpus Christi, established in 1263 by Urban IV., formally promulgated by Clement V. in 1311, and fifty years later amplified and rendered more magnificent by John XXIII. This festival was introduced into Spain during the reign of Alfonso X., and its celebration there, as elsewhere, was accompanied by dramatic representations. In Barcelona, even earlier than 1314, part of the celebration consisted in a procession of giants and ridiculous figures--a feature, as we shall afterwards see, always retained. It seems established that from the earliest date dramatic representations of some kind always accompanied the celebration of Corpus Christi. These plays, constituting a distinct and peculiar class, received a name of their own, and were at first called _autos_ (from the Latin _actus_, applied to any particularly solemn act, as _autos-da-fe_), and later more specifically _autos sacramentales_. We infer from occasional notices that these religious dramas were performed without interruption during the XIVth and XVth centuries. What their character was during this period we do not know, as we possess none earlier than the beginning of the XVIth century. From this last-named date notices of the secular drama begin to multiply, and we may form some idea of the early _autos sacramentales_ from the productions of Juan de la Enzina and Gil Vicente. The former wrote a number of religious dialogues or plays, which he named _eclogues_, probably because the majority of the characters were shepherds. One of these eclogues is on the Nativity, another on the Passion and Death of our Redeemer. The word _auto_, as we have stated, was applied to any solemn act, and did not at first refer exclusively to the Corpus Christi dramas, so we find among the works of Gil Vicente an _auto_ for Christmas, and one on the subject of S. Martin, which, although having nothing to do with the mystery of the Eucharist, was performed during the celebration of Corpus Christi in 1504, in the vestibule of the Church of Las Caldas in Lisbon. These sacred plays were undoubtedly at first represented only in the churches by the ecclesiastics; they were not allowed to be performed in villages (where they could not be supervised by the higher clergy), or for the sake of money. The abuses in their performance, or perhaps the large number of spectators, afterwards led to their representation in the open air. The stage (as in the beginning of the classical drama) was a wagon, on which the scenery was arranged; when the _autos_ became more elaborate, three of these wagons or _carros_ were united.