SIR -- On examing hair samples of mummies in the scanning electron microscope we found a piece of tissue between the curls which had the characteristic appearance of silk. To show that the specimen was silk, we performed infrared studies using multiple internal reflection, allowing nondestructive identification of the material. The spectra clearly identified silk.

We perfomred amino-acid anaylsis of the sample according to the method in ref. 2 and obtained the typical spectrum of hydrolysed silk, with high glycine, serine and alanine peaks as originally described by Shimura. To exclude the possibility that the silk specimen could have been added later to the mummy's hair we performed amino-acid racemization studies on the mummy's hydrolysed hair samples and on the hydrolysed silk specimen: proline racemization was used as the marker amino acid. We used an HPLC method for the separation of L and D forms.

The D/L racemization ratios from hair and silk were comparable, which excludes contamination of hair by the silk tissue in recent times. The mummy, a 30-50-year-old female, was found in Thebes, Deir el Medina, at the burial ground of the king's workmen. Based on anthropological data, the mummification method, the burial ground and amino-acid racemization, the mummy can be assigned to the twenty-first dynasty.

The silk industry had its origin in China and the material probably first reached the Mediterranean countries via Persia. Silk was not used in Egypt until later; the earliest example that can be traced is of Ptolemaic date from Mostagedda, a wollen tunic with decorative stripes with a weft of white silk. Lucan, writing in the middle of the first century, described Cleopatra with "her white breasts resplendent through the Sidonian fabric, which, wrought in close texture by the skill of the Seres, the needle of the workmen of the Nile has separated and has loosened the wrap by stretching out the web".

A portion of a coloured silk fabric was found at Qustul, south of Abu Simbel, the exact date of which is not certain, though it is probably not older than the fourth century AD. From the fourth century AD onwards silk became more common in Egypt. Our work suggests that silk was used in Egypt as long as 1,000 years BC, which would shed new light on ancient trading practices.