But as regards open screens the case is widely different; they existed under the form of trellis (opere reticulato) in the oldest churches, and, in succeeding centuries not only was every chancel and choir enclosed by them, but each chapel, and even altar; they were to be found in every parochial church, either of metal, stone, or wood; in Germany, Flanders, and the North, metal was the usual material, but in England and France stone and wood, while in Italy and the South they were usually composed partly of marble and partly of metal. But their use was universal, they commenced many centuries _before the introduction of pointed architecture_, and _they have survived its decline_; in fact, they belong to the first principles of Catholic _reverence and order_, and _not to any particular style_, though, like everything else connected with the church, they attained their greatest beauty in the mediæval period. The church of San Michele, at Florence, contains an altar erected in the fourteenth century, in honour of a venerated picture of the Blessed Virgin; it is a most interesting example of a detached altar surrounded by a screen. Like all the Italian mediæval works, it is exquisitely beautiful in detail, and admirable in the sculptured enrichments; it is entirely surrounded by a screen, partly composed of bronze and partly of marble, divided in open panels of pointed tracery; this supports a cresting, with prickets for tapers, and at the four angles are images of angels bearing metal candlesticks of elegant design. In order to convey a more perfect idea of this beautiful and decorated altar, I have figured it among the illustrations. In Ciampini's great work, "Vetera Monimenta," are plates of some of the altars which stood in old St. Peter's Church, at Rome, enclosed by brass screens, surrounded by standards for lights; and as a proof of the extent of this traditional enclosure of altars, when Antwerp Cathedral was restored to Catholic worship, after its pillage by the Calvinists in the sixteenth century, there not only was a great marble screen and rood loft restored across the choir, but a new range of altars having been set up against the pillars of the nave, each altar was enclosed by an open brass screen about six feet high, supported on a marble base, as may be most distinctly seen in a view of the church painted at the time by Peter Neefs, still preserved at Bicton House, near Sidmouth, and from which I have made the drawing etched in this work. I consider these authorities rather important, as when this church was restored for the Catholic worship all feeling for pointed design had been superseded by Italian; but change of detail had not then produced change of sentiment, and I shall clearly show that Catholic traditions, in this respect, have survived all changes of form and ornament.