At first, it was believed that the structure had been designed to prevent invasions, but a new study on the northern section of the wall suggests something else.
For a long time, it was thought that the Great Wall of China had been built to protect the Chinese Empire from the threat of invasions. However, a study by the Hebrew University of Jerusalem in Israel, published in Antiquity, suggests that the purpose of part of the construction was to monitor civilian movement.
For two years, a group of scientists led by archaeologist Gideon Shelach-Lavi first mapped a 740 km (460 mi) stretch of the Great Wall, called the Northern Line. This is how they discovered that, because it crossed many valleys and had a relatively low height, this part of the wall was inefficient for military functions, contradicting the hypothesis that the wall was only used for war.
“Our conclusion is that it was more about monitoring or blocking the movement of people and livestock, maybe to tax them,” said Shelach-Lavi, in a note. According to the researcher, it is very likely that groups would try to look for warmer pastures south of the wall during cold periods.
The construction of the Great Wall, which stretches over 21,000 kilometers (13,000 mi), began in the 3rd century BC and took hundreds of years to be definitively completed. The Northern Line, also known as Genghis Khan’s Wall – in reference to the legendary Mongol conqueror -, was built between the 11th and 13th centuries.
Researcher Shelach-Lavi and his team used drones, high-resolution satellite images, and traditional archaeological tools to map the wall; thus, they were able to find characteristics that helped them determine the dates of events. Until the publication of the new article, the Northern Line had been ignored by contemporary scientists.