Entering when the eyes have become accustomed to the obscurity, we make out the details of a very small and curious structure. Again to quote Mr. Street, the nave is only “21 ft. 7¼ in. by 20 ft. 2 in., and this space is subdivided into nine compartments by four very low circular columns, which are about a foot in diameter. Their capitals are all different. The arches, of which four spring from each capital, are all of the round horseshoe form; above them is a string-course, and all the intermediate walls are carried up to the same height as the main walls. They are all pierced above the arches with arcades of varied design, generally cusped in very Moorish fashion, and supported on shafts; and above these each of the nine divisions is crowned with a little vault, formed by intersecting cusped ribs, thrown in the most fantastic way across each other, and varied in each compartment. The scale of the whole work is so diminutive that it is difficult, no doubt, to understand how so much is done in so small a space; but looking to the early date of the work it is impossible not to feel very great respect for the workmen who built it, and for the ingenious intricacy which has made their work look so much larger and important than it really is.” After the Reconquest, the loftier portion of the temple, consisting of apse and transept, and containing the altar, was added. Looking closer into the details of the Moorish portion, one is struck by the contrast presented by rude shafts and capitals, evidently of Visigothic workmanship, with the general elegance and delicacy of the whole. On making a careful study of these features, it is difficult to resist the conclusion (supported, indeed, by tradition) that they formed part of an earlier and less skilfully constructed mosque, itself merely a restoration or adaptation of a Visigothic church. Señor Amador de los Rios is of opinion that the existing structure constituted only the inner portion or _maksurah_ of the temple, and believes that the southern wall is the only part of the outer or enclosing _enceinte_ remaining. In this he finds traces of the _kiblah_ or sanctuary, _membar_, and other features peculiar to Mohammedan worship. The mosque consisted originally, in all probability, in addition to the fabric we now see, of naves extending on each side of those still standing, from north-east to south-west. Even thus the mosque must have been very small. The exact configuration and plan of the original building is still a matter of great perplexity to archæologists, and a great many more discoveries remain to be made before anything can be positively stated under this head.