In the seventeenth century, however, the history of glass in France centres round the manufacture of plate-glass by the new process of _coulage_ or casting. After the middle of the century a demand arose in France for large sheets of clear glass, not so much for windows, it would seem, as for the tall mirrors that were now coming into fashion, and again for the _portières_ of the ‘glass-coaches’ of the nobility. Colbert, the great minister of the early and glorious days of Louis XIV., was in despair because the large panes of glass suitable for these purposes had to be obtained from Venice or from Nuremberg. After an unsuccessful attempt to establish a colony of Muranese workmen in Paris, Colbert had recourse to a Norman family of glass-makers, the De Néhou, who had lately succeeded the De Cacqueray at Tourlaville, near Cherbourg. It was in 1675 that Louis Lucas de Néhou was put in charge of the royal glass-works at Paris, where he perfected his great discovery of the method of casting glass. He was able to turn out sheets of unprecedented size by a process in which the ‘metal’ was poured upon frames, spread out evenly by rollers, and subsequently polished. The _Manufacture Royale des Glaces_ was removed in 1693 to the Château de St. Gobain, not far from Laon. The St. Gobain works have for two hundred years held a pre-eminent position in Europe for the manufacture of plate-glass. This subject of plate-glass is indeed a little outside our limits: for the student of the architecture and the decorative arts of the eighteenth century it is, however, one of no little importance. I have been able to do little more than select a few examples that have seemed to me of especial interest from the well-filled records of the French glass-workers of the sixteenth and seventeenth centuries, and many important centres have been passed over without comment,—Nantes, for instance, frequented above all by the Altarists; and Poitou, the source, according to M. Fillon, of many of the finest extant examples of French enamelled glass. In both these districts members of the Saroldo family settled—in Brittany they were prominent for over two centuries. In Paris, or rather in the Isle de France, the glass-works of St. Germain-en-Laye were for a time under direct royal patronage. It was there, soon after 1552, that Teseo Mutio made for Henri II. ‘_verres, myroirs et canons_.’[176] Although the king pronounced Mutio’s work to be equal to that of the Venetians, these glass-houses had but a short life. In 1604 a special commission was appointed in Paris to deal with the difficulty that arose from the obstinate refusal of the Altarists to teach the French apprentices the secrets of their craft. It was proposed to get over this obstacle by the naturalisation of the Italians, but to judge from the continued importation of fresh batches of foreigners, this measure had but little practical result.