The southern façade is flanked by sacristies, offices, and courts, above which appear the graceful flying buttresses, gargoyles, and windows, and the majestic dome of the main building. In the middle of this side is a modern entrance, the Puerta de San Cristóbal, added by Casanova in 1887. In the eastern façade are two entrances--the Puertas de las Campanillas and de los Palos--both enriched with fine sculpture by Pedro Millan; the Puerta de los Palos has also a fine Adoration of the Magi by Miguel Florentin (1520). On the northern side of the Cathedral we find the most important remains of the pre-existing mosque, the Giralda, already described, and the _Patio de los Naranjos_, with the original fountain at which the Muslims performed their ablutions. The _patio_ is entered from the street by the Puerta del Perdón, a richly decorated horseshoe arch erected by Moorish hands by order of Alfonso XI., to commemorate the victory of the Salado in the year 1340. In the sixteenth century this door was restored and adorned with sculptures. The colossal statues of Saints Peter and Paul, in terra-cotta, are the work of Miguel Florentin. He was among the earliest of the Renaissance sculptors to settle in Spain. By him also is the relief of the Expulsion of the Money-Changers from the Temple, celebrating the substitution of the Lonja or Bourse for this gate as a rendezvous for merchants. The plateresco work was executed by Bartolomé López in 1522. The doors date from Alfonso’s reign, and are faced with bronze plates, on which are Arabic inscriptions. Close to the Puerta del Perdón is a shrine built in the wall with a Christ on the Cross by Luis de Vargas. Entering the _patio_, to the right we find the Sagrario, or parish church, and to the left (reached by a staircase) the Biblioteca Colombina or Chapter Library, founded by Fernando Colon, son of Christopher Columbus. Among the treasures it contains are a manuscript of the great discoverer’s travels, with notes in his own hand; a manuscript tract, written by him in prison, to prove that the existence of America was not contrary to Scripture; the sword of Garcia Perez de Vargas, the great hero of the conquest of Seville, and a very interesting thirteenth-century translation of the Bible. The northern façade of the Cathedral is entered through three portals, the westernmost of which, the Puerta del Sagrario, is unfinished. The Puerta de los Naranjos and the Puerta del Lagarto lead from the _patio_. The Puerta del Lagarto retains some traces of its Moorish origin. It is named after the patched and painted stuffed alligator, which has hung here since about the thirteenth century. Here may also be seen a huge elephant’s tusk, and a bridle said to have belonged to the Cid.