Linen is often mixed with other fabrics such as cotton to create a soft fabric which will drape well. Whereas pure linen is known to crease (which is fine if you are creating a relaxed look) by mixing it with cotton you will get a more tailored look whilst keeping the luxury of linen.
Linen can also be mixed with polyester or viscose to give a hard-wearing fabric which is more crease resistant than pure linen fabric. By blending with a synthetic the fabric can also be less expensive.
Blending linen with silk fabric is another popular mix which produces a natural and luxurious fabric, ideal as a curtain fabric as it will drape beautifully, especially for full length curtains where it will look stunning.