The introduction of the new enamel, which afforded a better ground for painting, did not cause the use of the bright metallic colours and prismatic glaze to be relinquished at those potteries where it had become established, but it appears to have stimulated a development in the artistic productions of other places, the wares of which before that period were less attractive. The botega of Maestro Giorgio at Gubbio seems to have been at this time the great centre of the process of embellishment with the golden and ruby metallic lustres; and, indeed, we have little or no knowledge of artistic pottery produced at that fabrique which is not so enriched. From some technicality in the process of the manufacture, some local advantage, or some secret in the composition, almost a monopoly of its use was established at Gubbio, for we have the evidence of well-known examples that from the end of the first to the commencement of the last quarter of the 15th century many pieces painted by the artists of Pesaro, Urbino, and Castel Durante, were sent there to receive the additional enrichment of the lustre colours. Pieces may be seen in collections signed in blue by the artist Francesco Xanto and others which have been subsequently lustred at Gubbio, and again signed in the metallic pigment by the “maestro” of that botega. At Diruta also its use appears to have been extensive though not to so exclusive a degree nor on wares of such high character as at Gubbio, neither are we enabled by the possession of examples to conclude that the works or other fabriques were sent to Diruta for the additional embellishment. The crude drawing of the earlier ware improved very slowly; in 1502 tiles executed for the palace at Pesaro were still of sorry design; but it developed by the introduction of half tints, the colouring of the drapery, and in the composition of the groups of figures, inspired by the works of Timoteo della Vite and other artists of the Umbrian school. At Pesaro the art appears to have attained its highest perfection at the botega of the Lanfranco family, about 1540-45.