The two chapels next to that of the Constable on the north side of the apse are earlier than the others and are of good middle-pointed style. The chapel of San Gregorio seems to be the only one belonging to the thirteenth-century church. It contains the tomb of Bishop Fontecha. The adjoining chapel of San Nicolás was built in 1268 by Bishop Villahoz, whose tomb and effigy are placed upright against the wall. Close by is one of the finest sepulchres in the cathedral--that of the Archdeacon Fernando Villegas, an early translator of Dante. Opposite the door of the Nacimiento chapel is a notable picture of San Juan de Ortega by Cuadra.
At the northern end of the transept is the grand staircase of thirty-eight steps, leading to the Puerta Alta. It is one of the finest examples of the art of Diego de Siloe, who was at his best when handling such intricate and profuse decoration as this. The splendid iron balustrade was the work of Cristobal Andino.
Opening on to the north aisle are the large chapels of Santa Ana and Santa Tecla. The former was founded in 1474 by Bishop Luis Osorio Acuña, whose tomb is here. A much finer altar and monument in the Gothic style is that of the Archdeacon Fernando Diez de Fuente Pelayo, who died in the memorable year 1492; it is in white marble and adorned with sculpture with New Testament subjects, a good deal damaged. There are a few good pictures in this chapel, one attributed to Andrea del Sarto, and a sculptured genealogy of the Virgin. Of the chapel of Santa Tecla, perhaps not much else need be said than that it is in the Churrigueresque style and was founded in 1734. Its best feature is its ‘half-orange’ dome. O’Shea says that there formerly existed on the side of the baptistry a small chapel dedicated to Santiago, wherein Alfonso XI. instituted the order of knighthood of La Vanda or the Badge, of which the kings of Castile were members.
Opening on to the southern aisle, opposite the Capilla de Santa Tecla, is the cruciform chapel of the Santisimo Cristo de la Agonia, containing a very ancient, curious, and (it is alleged) miraculous image of Christ. It is supposed to have been carved by the fearful Nicodemus, and to have been afterwards found floating in a boat on the sea. It is a grotesque and yet a weird and impressive object, dressed up after the ridiculous custom in Spain.