A durable and breathable textile suited to warm climates, linen is made from the stem fibres of the flax plant Linum usitatissimum. One of the oldest textiles in the world, it features prominently in the history of agriculture and world trade, though today it is a relatively niche fabric. Its popularity declined with the cheaper mass production of cotton and other textiles from the eighteenth century.

Flax fibres are stronger and much longer than cotton fibres, with whom they share some chemical similarities. They are between 30 and 90 centimetres long, with a natural colour ranging from light brown to light grey. Because of the fibres’ high absorbency and good conduction of heat, linen both absorbs moisture and dries quicker than cotton. It is also relatively resistant to degradation by the sun. These qualities make it very suitable to wear in warm conditions; some research has also found it to have hypo-allergenic and anti-bacterial properties. The stiffness of linen fibres makes the fabric prone to wrinkling.

The production and processing of flax fibres for linen yarn is a labour-intensive and time-consuming process, but with a relatively small environmental impact, especially in temperate and sub-tropical regions of the world where flax grows easily. In warmer climates it can be grown with the additional support of fertilisers, pesticides and irrigation. Flax is a bast fibre, obtained from the inner bark or phloem of the plant stem. To maximise fibre length, flax seeds are sown close together so that the plants grow upwards instead of branching out. Once they have reached the desired height and maturity, which takes over three months, the stalks are pulled from the soil by hand, packed into sheaves, and dried over two weeks. The seeds are removed in a process called rippling. 

The next step is retting, a crucial process of fermentation that breaks down the compounds binding the fibres, thereby releasing them from the rest of the stalk — this is done through prolonged exposure to moisture, either by spreading the stalks out in the field to be ‘dew-retted’ or submerged under a pool or stream of water to be ‘wet-retted’. After this, the stalks are dried fully and scutched (beaten), and finally combed to remove any non-fibre material. The coarse fibres are also separated. The remaining long, fine-grade fibres, called dressed flax, are spun into yarn for linen; they are often subjected to additional treatment processes to make them softer and more lustrous. The shorter, coarser fibres left behind are used to make goods such as canvas, fishing nets and twine, or combined with other fibres such as cotton to make blended fabrics.

Fragments of flax fibres used by humans, including dyed fibres, have been found in caves in present-day Georgia and the Czech Republic, dating as far back as 34,000 years. There is evidence of linen being woven since at least as early as 8000 BCE. It was widely used for clothing in ancient Egypt, and was also used to wrap mummies — well-preserved linen dating to 3000 BCE has been found in Egyptian tombs. With Phoenician trade from the fourth millennium BCE, knowledge of linen production was dispersed across the Mediterranean, and had arrived in the Indian subcontinent at least by the second or first millennium BCE.

Linen is mentioned as a ceremonial fabric, referred to as kshauma, in the Vedas and the epics Ramayana and Mahabharata. During the reign of the Maurya dynasty (between the fourth and second centuries BCE), flax was cultivated as a cash crop, and the Arthashastra, thought to have been composed around this time, details the production of linen and mentions imperial linen weaving centres in present-day Assam. In the ancient period, the textile finds mention in the accounts of travellers such as the Chinese monk Xuanzang in the royal court of king Harsha Vardhana (r. 606–641 CE) of Kannauj (in present-day Uttar Pradesh).

By the Middle Ages flax and linen manufacture and trade were thriving in Europe, with Germany and Ireland as significant centres. Linen was the most popular and preferred summer fabric in the West until the nineteenth century, when it was largely replaced by cotton, which was mass produced and more easily accessible through innovations introduced during the Industrial Revolution. 

Flax makes up less than 1% of textile fibres used globally today, with the European Union ranking as the largest manufacturer in the world. Linen is mainly used to make clothing, and for bedspreads and other domestic textile products, which have also collectively come to be termed as ‘linen’, regardless of the material they are made from. Flax is also combined with other fibres to make a variety of blended fabrics.