The most important of the buildings of Alfonso is the Cámara Santa of the cathedral, once the Capilla San Miguel, which was part of the original church of Alfonso, and was built in the eighth century by his architect Favila. The room itself is small, without ornament, roofed with low barrel vaulting, and lighted with one small window. But here are guarded the relics in the Byzantine-Latin style, which are among the most interesting examples that remain to us of the work of the period. The Cruz de los Angeles, a work of the eighth century and the gift of Alfonso II., and the Cruz de la Victoria, supposed to have belonged to Pelayo, both resemble very closely the crowns of Guarraza; like them, they are not typically Spanish work. That of the Angeles is of filigree work of exquisite delicacy, and enriched in the centre with rare encrusted rubies and other precious stones; while that of the Victory is made of wood, but Alfonso III. had it overlaid with gold and ornamented with jewels. A third relic, the cash-box of St. Eulalia, has its chief interest in the inscription in Arabic and Cufic characters which surrounds the cover. A special historical interest belongs to the relic known as the Arca de los Santos. The cover, on which is engraved the figures of the Apostles, and the Latin inscriptions belong, by the character of the vestments, which are those described by St. Isidore, and by the letters used, to the sixth or seventh centuries; while the Saviour and angels on the box itself, the inscriptions in Cufic lettering, as well as the general style of reliquary, have the characters which belong to the Spanish works of the eleventh and early years of the twelfth centuries. The explanation, of course, is that the casket was restored and its character altered at a later date, and probably in the reign of Alfonso VI. This mingling of different styles and periods in one work of art meets us continually in Spain. It is due in large measure to the custom by which the Spaniards used and borrowed the arts of the Moors, even for long after they had conquered them. There are a few works in the Madrid Archæological Museum which are in the Latin-Byzantine style, and should be compared with the treasure of the Cámara Santa, and to the same period belong other relics now in different churches in the Peninsula.