This undated file photo provided by the National Cultural Heritage Administration (NCHA) shows a view of an underwater shipwreck from the Yuan Dynasty (1271-1368) near the islet of Shengbeiyu in the city of Zhangzhou, southeast China's Fujian Province. (NCHA/Handout via Xinhua)

More than 700 years ago, a vessel loaded with porcelains sank off the coast of east China's Fujian Province while en route overseas.

The underwater wreckage near the islet of Shengbeiyu in the city of Zhangzhou was recently unveiled in an archaeological salvage project, presenting to the world the historical prosperity of the Maritime Silk Road during that era.

The salvage, which kicked off in September last year and lasted until this month, was jointly conducted by the National Centre of Archaeology (NCA), the Fujian provincial research institute of archaeology and the Zhangzhou municipal bureau of culture and tourism.

Located at the intersection of the eastern route and the southern route of the ancient Maritime Silk Road, the sea waters near the Shengbeiyu islet is a shipwreck-prone area as it is surrounded by reefs and has complex sea conditions.

The ship from the Yuan Dynasty (1271-1368) was found there under the sediment at a water depth of about 30 meters.

Nearly 20,000 items have been retrieved, with the collection comprising over 17,100 Longquan Celadon porcelains, renowned in China for their exquisite colors, particularly the shades of jade green and light blue. Bowls, plates, cups and incense burners are among the retrieved porcelains, which are believed to have been produced in the late Yuan Dynasty.

"The sunken ship contains the largest number of Longquan porcelains found onboard to date, serving as a typical example of the Longquan porcelain exports peak of the late Yuan Dynasty," said Chen Hao, deputy head of the underwater archaeology center of the Fujian provincial research institute of archaeology.

Some porcelains were engraved with characters, such as "Yong," "Bao" and "Nian," meaning "use," "treasure" and "year," respectively. These porcelains have become important materials for research on the export of Longquan porcelains, Chen said at a press conference held earlier this month.

According to Chen, the discovery also ascertains that the government back then encouraged overseas trade, making the Maritime Silk Road especially prosperous in the Yuan Dynasty.

Among the porcelains found were giant plates with a diameter of 35 cm and a height of 4.3 cm, rarely seen in China.

Liu Miao, an associate professor at Xiamen University, said the big plates were produced based on overseas dining customs, an apparent customized design for porcelain exports.

Combining the archaeological findings at an ancient port in the city of Wenzhou in Zhejiang Province and the high similarity between archaeological discoveries of the sunken ship and the porcelains excavated in Southeast Asia, experts assume that it was a civil merchant ship setting off from the port of Wenzhou to Southeast Asia.

The salvage project team for the first time adopted underwater photographic stitching to obtain a panoramic high-definition three-dimensional image of the wreck site in low visibility sea conditions.

Liang Guoqing, the team leader who works with the NCA, said they previously thought the ship had seven cabins. However, as the dredging work went on, they found it had 10 cabins, indicating that it was a large merchant ship for trade.

Liang added that the salvage project involving the sunken ship is a milestone in China's underwater archaeology history.

"The discovery has enabled people to get a glimpse of the booming trade of Longquan Celadon porcelains as well as the prosperity of the Maritime Silk Road," he said.