Silk – the last natural fibre, following on from wool, linen and cotton, which we’ve covered in previous articles here – is an animal fibre produced by certain insects and arachnids when building their webs and cocoons. Almost all commercial silk textiles derive from the cocoons of domesticated silkworms: the caterpillars (larvae) of moth species belonging to the genus bombyx .

The production of raw silk by raising silkworm caterpillars, or sericulture, entails their care from egg stage to completed cocoon, including growing the mulberry trees on whose leaves they feed. To construct their cocoons, silkworms secrete a glandular liquid that dries into strands of fibroin (a protein) and another stickier substance, sericin, that binds the fibres into the long, unbroken ‘filament’ that the silkworms wind about themselves. The continuous filament or ‘silk’ within each cocoon has a usable length of c.600–900 metres; however each filament is cobweb thin, so several cocoons are ‘reeled’ together and twisted slightly into a single silk strand. Several strands are then again twisted together in a process called ‘throwing’ to produce thicker, stronger yarn. Raw silk retains the gummy sericin, but when boiled away in soap and water, the yarn is soft, lustrous and semi-transparent, its weight or thickness expressed in denier (as in, for example, women’s stockings and tights). Silk is strong and stretchy, yet finer than cotton or wool; it is also moisture absorbent and has excellent dyeing properties.

The origins of silk production are shrouded in legend, but evidently sericulture began in China in the third or fourth century BC, where it long remained a closely guarded secret. However, eventually, with Chinese expansion from c.114BCE, goods and knowledge began to be traded westward along the famed Silk Road – a series of what today’s historians term ‘Silk Routes’ starting in Peking, traversing central Asia, passing through Baghdad, Palmyra, then either onto Aleppo and the Levant, or to Cairo and North Africa. Via such routes, the Byzantines were able to begin silk cultivation during the 500s, and by the 700s/800s it was known in the Aegean, while the Moors introduced silk to Spain. Between the late 1000s and 1200s the Crusades brought Europeans into greater contact with eastern luxuries and major silk production commenced in many Italian states including Florence, Venice and Lucca.

Among the coveted silk textiles of this era were sumptuous woven damasks and samites – heavy, richly dyed, patterned silks with a satin-like sheen, these sometimes further embellished with jewels, pearls and embroidery. The most ornate and luxurious materials of the early medieval world, silks were enjoyed by the high ranking everywhere: tenth century Vikings were buried in silver-embroidered silk samite cloth; Christian and Muslim royalty wore silk robes and dressed their homes in damask; the higher clergy wore vestments of embroidered samite; and even the horses of the elite wore patterned silk saddle cloths. {