That Mosaic should be popular with the Romans was natural, since their thoughts, mythology, social and philosophical systems, exhibited only one vast composition made up of precious fragments plundered from the East, and maintained in a gorgeous form on their grand system of forcible compact and consolidated union. Pliny states that Scylla was the first Roman who caused stone-laid work to be produced, about B.C. 80. Many elegant spoils from Greece were deposited in the temple of Jupiter Capitolinus, and were probably adopted as decorations, which created in the minds of luxurious and ostentatious patricians an anxiety for other magnificent embellishments, and thus occasioned Mosaic. The most noble specimen of it now extant is the splendid pavement of the Pantheon, the historical worth of which is commensurate with its great superficial extent. Porphyry, Giallo Antico, and Pavonazzetto are the principal marbles employed, and they are arranged simply in round and square slabs. Fine fragments have been found in the Baths of Caracalla, and are preserved, with numerous other specimens, in the great Mosaic depository of the Vatican. The most generally known, and by far the most exquisite example of this art still existing, is the picture usually called "Pliny's Doves." It is in the museum of the Capitol, and represents a metal bason, on the edge of which four doves are sitting; one of them is stooping to drink, and not only the shadow cast by it, but even the reflection of part of the head in the water, is beautifully shown. The vast accumulation of precious material after each campaign greatly enhanced the passion for Mosaic decoration, and it was copiously produced till the end of the second century. The church early adopted this art for sacred symbolic purposes, and during the mediæval period, carried it to the highest perfection. The only specimen of primitive work now extant, is the curious incrustation which lines the vaulting of the Baptistery erected by Constantine, dedicated to Santa Constanza, and which represents a vine covering, as it were, the whole roof.