The archaeological site in Jinsha Village, in the western suburbs of Chengdu in Sichuan province, has shown the world that a stable and religious civilisation flourished there some 3,500 years ago, modifying previous assumptions about the origins of Chinese civilisation. The site, discovered in 2001 by a housing development company, continues to yield a stream of art works and religious symbols.

Jade and gold artefacts resembling finds at the nearby site of Sanxingdui, 40km from Chengdu, reinforce the theory of a powerful kingdom believed to be one of the oldest in the world. Historians think these are the remains of the ancient Shu kingdom mentioned in stories of the Han and Qin dynasties 3,000 years ago.

The sophisticated craftsmanship of the artefacts and the presence of non-indigenous copper, tin, bronze and ivory point to a complex society that traded with other societies from the Yellow River to the north and modern-day Thailand to the south.

The discovery of objects of obvious religious significance at Jinsha and Sanxingdui has given rise to various theories on the origins of the Jinsha kingdom. The jade heads, with stretched faces and elongated pointy ears, found at both sites could have hailed from Southeast and Central Asia. Sun and tree worship were widespread in contemporary societies, especially in ancient Mesopotamia, and trade in ivory can be traced to Southeast Asia, Mesopotamia and Africa.

The unfinished nature of many of the artefacts has led researchers to believe that the site was a political and spiritual centre of the ancient Shu kingdom, and a workshop supports the theory of a trading network spanning China and beyond.

Chengdu's written history as a city goes back more than 2,000 years to Zhang Yi, a descendant of an aristocratic family of the Wei dynasty who helped build the city during the Warring States Period (475-221BC). Historians are convinced that this had been an important regional centre for thousands of years.

But the origins of the ancient Shu are still vague. What is certain is that the kingdom fell suddenly 3,000 years ago, and remained hidden until the 20th century.

Jiang Zhanghua of the Chengdu Historical Relics and Archaeological Research Institute has devoted the past 20 years to research into the ancient Shu kingdom. He has amassed a collection of literature and pictures that paint a reasonably clear picture of Sichuan's ancestors.

Burial pits in Jinsha, similar to ones found in Sanxingdui in 1985, contained tusks, antlers and teeth from some 500 elephants, 1,000 deer and 1,500 wild boar. Dozens of carved jade, gold, stone and ivory artefacts suggest ceremonies to celebrate a new year, eulogise a dead king or ensure continued prosperity.

Mr Jiang believes the Sanxingdui culture fell as the Jinsha kingdom rose.

The Chengdu archaeological team and historians from across China are still gathering evidence in the Jinsha area. Meanwhile, the municipal government has started constructing a museum to house these finds. It is due for completion by the end of this year.