A stone tablet, dating back to the reign of Emperor Wanli in the Ming Dynasty (1368-1644), has been discovered on top of a tower on the Great Wall in North China, local authorities said.

The tablet, 102 cm long, 62 cm wide, and 13 cm thick, was found by a so-called "protector" (or guard) while patrolling the Xuliukou section of the Great Wall in Qian'an, Hebei province, according to sources with the city government.

With a 300-character inscription, the tablet recorded the names and titles of 15 officials in the Ming Dynasty.

The officials inscribed on the tablet were the main generals who helped build this section of the Great Wall, and the officials who guarded it in the later period, said Guo Lifei, vice curator of Qian'an Museum.

"According to the inscription, the tablet was erected in 1584. It is the best-preserved stone tablet discovered along the Great Wall section of Qian'an, and can provide a reference for studies on the Great Wall culture and the rank system of the Ming Dynasty," said Guo.

The Great Wall is a UNESCO World Heritage site, consisting of many interconnected walls. It traverses through several provincial-level regions and cities in China.

Due to human destruction and natural weathering, some parts of the Great Wall have been damaged or collapsed and are in urgent need of renovation.

Qian'an has a total length of 45.3 km of the wall, mainly built in the Ming Dynasty. To protect the cultural relics, the city has hired 24 protectors from surrounding villages.