A long-running exhibition, Treasures of the Great Tang Dynasty – Exhibition of the Unearthed Relics from Hejia Village, reopened on Tuesday after a one-month closure in the Shaanxi History Museum in Xi'an, capital of Shaanxi province.

The exhibition opened on April 6, 2010 and was closed from Jan 1 to Monday while maintenance was done on the relics.

"The relics had been displayed for a long time and exposed to air, visitors' breath and camera flashes, which harmed the relics. They needed to be maintained to better protect them," the museum said.

The exhibition displays more than 300 groups of rare relics made in the Tang Dynasty (618-907), of which there are four national-level cultural relics.

The relics were discovered in October 1970 when a piece of rare relic was accidently unearthed at a construction site in Hejia village in southern suburban Xi'an. Archaeologists excavated the site and found more than 1,000 relics, including gold and silver wares, jewelry, ornaments and precious Chinese medicine, as well as Chinese and foreign coins. They were put in two big urns and a jar, and were considered one of the 20th century's most important archaeological discoveries from the Tang Dynasty.

The place where the relics were unearthed was called Xinghua Square in Chang'an city during the Tang Dynasty. According to historical records, a number of official and residential buildings for senior officials and rich businessmen were concentrated in Xinghua Square. The relics were thought to be left by one of them.

The discovery was of great significance because it was the first – and only – time so many rare gold and silver pieces from the Tang Dynasty were found in one place.