Towards the beginning of the eighth century the Arabs introduced the silkworm into Spain. But this industry remained confined within narrow limits. It was in fact not till after the twelfth century that sericulture began to spread throughout Europe. Roger, King of the Two Sicilies, possessing a navy that commanded the Mediterranean, employed it chiefly in making excursions and conquests. He ravaged Greece, and, not satisfied with the booty he carried away from that unfortunate country, wished still further to deprive them, for the good of his own kingdom, of the silk monopoly, the source of their riches. Roger carried away into Sicily and Naples a great number of prisoners, amongst whom were some weavers and men who had devoted themselves to the rearing of silkworms. In 1169 he established these workmen in houses adjoining his own palace at Palermo. There they dyed the silk of different colours, and mixed it with gold, pearls, and precious stones. From Sicily the art of preparing silk spread over the rest of Italy. In 1204 the workers in silk constituted themselves into a syndicate at Florence. It is not, however, till 1423--more than two hundred years after the introduction of this branch of industry into Italy--that we find the first mention of the cultivation of the mulberry tree in Tuscany. In 1440 each Tuscan peasant was forced to plant at least five mulberry trees on the land he cultivated. In 1474 the commerce in silk fabrics with all parts of the world had become extremely prosperous at Florence. In 1314 the Venetian manufactures began to assume much importance. Three thousand workers in silk were then established in Venice. Without dwelling longer on the propagation of the silk trade in Italy, let us pass on to its establishment in France. It was in 1340 that some French gentlemen, who had stayed some time in Naples, planted in Avignon the first mulberry trees.[58] According to Olivier de Serres, it was not introduced till much later into Dauphiné. It was not introduced into Alan, near Montelimart, till 1495, by the Seigneur Guyape de Saint-Aubain.[59] Louis XI. made great efforts to develop the silk trade in France, by inviting over Italian workmen; and they began under his reign to fabricate silks in Touraine and Lyons. Francis I. greatly developed the trade of Lyons. In 1554, under Henry II., the masters and men employed in the manufacture of gold, silver, and silk in Lyons were twelve thousand in number. Under Henry II. were planted the mulberry trees of Bourdezière, Tours, Chenonceaux, Toulouse, and Moulins. These plantations, however, were of very small extent. They were not the result of a general and truly popular effort; moreover, civil war came very soon, and turned men's minds away from the isolated attempts of some few private individuals. Sericulture, in fact, did not assume any great importance in France till the reign of Henry IV. [58] De Gasparin, "Essai sur l'Introduction des Vers à Soie en Europe," p. 70.