The silk costumes were believed to belong to noble women in the Tang Dynasty (618-907 AD), the most prosperous and powerful feudal dynasty in China's history. They were unearthed in 1987 from an underground chamber at the Famen Temple, a royal temple in the Tang era some 118 km (73 miles) west of Xi'an, the provincial capital of Shaanxi.

The Famen Temple, reputed as a "treasure house" of Tang relics, also houses the remains of finger bones of Sakyamuni, the founder of Buddhism.

Unfolding the six ancient dresses was a "major breakthrough" for Chinese archaeology and also provided vital clues for the study of Chinese costumes and social customs some 1,000 years ago, said Han Jinke, curator of the Famen Temple Museum.

The dresses came to light along with more than 700 other Tang period silk goods, all of them entangled in piles or stuck together because of underground dampness and pressure from the repeated collapse of surface structures.

The silk products of the Famen Temple represented the world's most sophisticated silk technology in that age, said Han. The diameter of gold threads used for embroidery on the dresses measured only 0.1 mm, even thinner than human hair, he noted.

However, it took the Chinese scientists 15 years to work out a reliable way to separate the ancient silks without damaging them. Initially the dresses had to be preserved at an extremely low temperature to keep them from decaying and their color from fading.

In March this year, China established its first laboratory for silk preservation, a 350,000-Deutschemark (US$200,000) joint project between China and Germany, which shed new light on separating the Famen Temple Tang silks.

Angelika Sliwka, a 44-year-old German silk expert who played a major role in the Famen Temple project, said the project involved archaeologists, scientists, silk experts and even meteorologists from both countries. Sliwka herself has 12 years' experience in ancient silk preservation and restoration.

The researchers first made a meticulous study of the ancient silk's original state, checking historical records about Tang Dynasty silk and collecting detailed data about the environment and climate in the Famen Temple area before working out a separation and restoration plan, said Sliwka.

Due to different features of the silk products, researchers had to apply varied techniques to every piece of silk they worked on, she added. The unfolding and restoration of each silk dress had at least six steps and took quite a long time.

Now that six unfolded dresses had been added to the Famen Temple Museum collection and put on display. The scientists were working to find out a faster and better way of dealing with the rest of the silks, said Han.

The pile of silk excavated from the Famen Temple comprised some 780 layers with an overall thickness of 23 cm (9 inches). If completely separated and unfolded, it would cover an area of more than 400 square meters (478 square yards), Han said.

(Xinhua News Agency July 13, 2002)