Silk cultivation started in Europe in early 10th Century (C.E.), first in Southern Spain then in Sothern Italy (early 11th Century). The silkworms were fed with Black Mulberry (Morus Nigra) only. Morus Nigra was indigenous to Europe. In early 15th Century the Chinese White Mulberry (Morus Alba) arrived in Italy. Morus Alba spread in Northern and Central Italy in the first half of 15th Century. From Italy Morus Alba was introduced in Southern Spain (Valencia, Murcia). Gradually, in the course of subsequent 3-4 Centuries Morus Alba substituted Morus Nigra to feed silkworms in Europe. The raw silk threads obtained by the use of Morus Alba leaves appears to have been softer than that raw silk obtained by the use of Morus Nigra leaves. Morus Alba widespread use appears to have improved the quality of raw silk threads as well as the quality of luxury silk fabrics produced in silk industry in selected Italian silk fabrics centers, such as Lucca, Bologna, Venice. Such centers, Lucca above all, had been importing huge amounts of raw silk threads from Central Asia and China in 12th to late 14th Century (C.E.), that is before the spreading of Morus Alba in 15th Century in Italy.