The art of architectural design received great assistance in Venice during this period, from the works of Sansovino, Palladio, and other consummate architects, who gave finished examples of magnificent edifices; while Daniel Barbaro composed very useful treatises upon perspective; and it became an attribute of the art to feign colonnades, galleries, and rich cornices, for those halls in which real architecture would not admit of them. In this, Cristoforo and Stefano Rosa more particularly distinguished themselves. They were from Brescia, very intimate with Titian, and merited the honour of being employed by him, in his architectural ornaments for several of his pieces. In Brescia, in Venice, and particularly in the anti-chamber to the library of S. Mark, we may meet with some of their perspectives, so admirably executed as to surprise us by their air of majesty, cheating the eye by their relief; and when beheld in different points of view, always producing a good effect. Their school continued to flourish during many years, in their native state; and was subsequently supported by Bona, excellent also in figures, as well as by other artists. Boschini bestows many commendations upon it in different parts of his work in verse; and in particular at p. 225, where he declares, that Brescia was the source of this art; which applies of course to the Venetian state. Finally, the art of mosaic work, in stone and coloured glass, at that time, attained such a degree of perfection in Venice, that Vasari observed with surprise, "that it would not be possible to effect more with colours."[76] The church and portico of S. Mark remains an invaluable museum of the kind; where, commencing with the eleventh century, we may trace the gradual progress of design belonging to each age up to the present, as exhibited in many works in mosaic, beginning from the Greeks, and continued by the Italians. They chiefly consist of histories from the Old and New Testament, and at the same time furnish very interesting notices relating to civic and ecclesiastical antiquity. A portion of the most ancient specimens had long either perished, or fallen into decay, and it had been resolved to substitute fresh ones in their place. It is not improbable, that after the year 1400, upon the revival of painting, a desire prevailed to banish the taste of the Greeks; and certain it is, that in the mosaics of that age we meet with the modern antique style, the same as in regard to pictures. It will be enough to cite the chapel of the _Mascoli_, decorated by Michele Zambono with histories of the life of the virgin, executed with extraordinary care, and designed in the best taste of the Vivarini.