The colour of the whole interior is, to my mind, charming. It was first of all built in alternate and very irregularly divided courses of brick and stone. On this warm-coloured ground, one pious man after another came and painted what seemed to him best--a Madonna, a crucifixion, a saint, or a group of figures--with not much thought beyond that of making the particular work in which he was interested tell its own story well and produce its own effect. So little did he think of other men's previous work that the same subjects are not unfrequently repeated. The result is that the walls were here sober and there gorgeous, but everywhere coloured, and everywhere more or less interesting. Yet the materials of which they are built are just those which we see every day of our lives, and it was the skill of the workman, not the richness of his materials, which made his work so worthy of our admiration.
Only one portion of the church is decorated upon a regular system; this is the eastern part of the choir and the apse, which has part of its walls and its groining very elaborately painted, though with but little gold; the groining ribs are richly coloured, and on each side of them is a wide border, generally subdivided into regular geometrical figures, and the spaces between these borders are painted blue and powdered with gold stars. In the south aisle is an altar under a baldachin, supported at the angles by four clustered shafts knotted together in mid height--a capricious custom of which Italians seem to have been especially fond, and the only excuse for which, so far as I can see, is that it proves that all the shafts were cut out of one block, and therefore of more value than four plain detached shafts cut out of separate blocks could be. There is perhaps, also, a relief to the mind, after looking at a long series of similar shafts, to come at last upon some one or two marked by capricious singularity such as this. Be this, however, as it may, the eye certainly always feels inclined to admire them, though the reason is never quite satisfied; and perhaps some better excuse does exist for their use than I have as yet been able to discover. It is probable that these columns belonged originally to the baldachin over the high altar. The canopy which they now support is not old.