Relics are seen in the wrecked ship "Nanhai No 1" at a museum in Hailing, South China’s Guangdong province, Dec 30, 2014. [Photo/IC]

An important step has been made in the recovery of thousands of relics from a famous Song Dynasty ship which sunk in the South China Sea about 800 years ago.

After one year of hard work, silt covering thousands of artifacts loaded within the ship has been largely cleaned up. The mystery shrouding the ancient merchant ship and its treasures could soon be lifted.

It's estimated that there are 60,000 to 80,000 relics inside the ship, including gold artifacts, brass and iron wares, and a large amount of porcelain. Now that the mud and silt has been mostly cleaned up, one can see densely arranged relics exposed.

The discovery of the sunken ship in 1987 was said to shed new light to the marine silk road, through which China's silk, porcelain and other artifacts were transported to Southwest Asia, the Middle East all the way to Africa and Europe. But the wreckage was not lifted from the ocean floor until December 2007.

It was then placed in a pool-type container called the "Crystal Palace", which became part of a Marine Silk Road Museum built on the site, in the city of Yangjiang, Guangdong province.

At the museum, visitors can witness the salvage process, and marvel at the thousand artifacts already extracted from the ship. Made of gold and porcelain by Song artisans, they were meant to be sold overseas. Some of the more recently restored relics bear strong influences from mid-western Asia.

Nanhai One is the oldest and largest sunken ship ever found in China. The remaining ship body is 21.8 meters long, with 13 large cabins to contain goods. It's expected to take another two to three years to take out all the relics from the wreckage.

Related: Large number of relics found in ancient ship Nanhai No 1