There is a little chapel opening to the east out of the northern transept arm which is full of interest from the fact that it belongs to the original, early thirteenth-century structure. Probably there was a corresponding one in the southern arm, with groining equally remarkable. The northern transept arm is filled by the great Renaissance "golden staircase" leading to the Puerta de la Coroneria, now always closed. It must have been a magnificent spectacle to see the purple and scarlet robes of priest and prelate sweep down the divided arms of the stair uniting in the broad flight at the bottom. Such an occasion was the marriage in 1268 of the Infante Ferdinand, son of Alfonso the Wise, to Blanche of France, a niece of Saint Louis. The learned monarch ever had a lavish hand, and he spared no expense to dazzle his distinguished guests, among whom were the King of Aragon and Philip, heir to the French throne. Ferdinand was first armed chevalier by his father, and the marriage was then celebrated in the Cathedral of Burgos with greater pomp and magnificence than had ever before been seen in Spain. The gilt metal railing is as exquisite in workmanship as in design, carried out by Diego de Siloé, who was the architect of the Cathedral in the beginning of the sixteenth century. There is also a lovely door in the eastern wall of the southern transept, now leading to the great cloisters. The portal itself is early work of the fourteenth century, with the Baptism of Christ in the tympanum, the Annunciation and David and Isaiah in the panels, all of early energy and vitality, as full of feeling as simplicity. And the extraordinary detail of the wooden doors themselves, executed a century and a half later by order of the quizzical-looking old Bishop of Acuna, now peacefully sleeping in the chapel of Santa Anna, is as beautiful an example of wood-carving as we have left us from this period. If Ghiberti's door was the front gate of paradise, this was certainly worthy to be a back gate, and well worth entering, should the front be found closed. The choir occupies at present as much as one half the length of nave from crossing to western front, or the length of three bays. With its massive Corinthian colonnade, masonry enclosure and rejas rising to the height of the triforium, it is a veritable church within a church. The stalls, mostly Philip of Burgundy's work from about the year 1500, surround the old tomb of the Cathedral's noble founder. As usual, the carvings are elaborate scenes from Bible history and saintly lore,--over the upper stalls, principally from the old Testament, and above the lower, from the New.