The one thing most people “know” about the Great Wall of China—that it is one of the only man-made structures visible from space—is not actually true. Since the wall looks a lot like the stone and soil that surround it, it is difficult to discern with the human eye even from low Earth orbit, and is difficult to make out in most orbital photos. However, this does not detract from the wonder of this astounding ancient structure.
For millennia, Chinese leaders instituted wall-building projects to protect the land from northern, nomadic invaders. One surviving section of such an ancient wall, in the Shandong province, is made of hard-packed soil called “rammed earth” and is estimated to be 2,500 years old. For centuries during the Warring States Period, before China was unified into one nation, such walls defended the borders.
Around 220 B.C.E., Qin Shi Huang, also called the First Emperor, united China. He masterminded the process of uniting the existing walls into one. At that time, rammed earth and wood made up most of the wall. Emperor after emperor strengthened and extended the wall, often with the aim of keeping out the northern invaders. In some places, the wall was constructed of brick. Elsewhere, quarried granite or even marble blocks were used. The wall was continuously brought up to date as building techniques advanced.
Zhu Yuanzhang, who became the Hongwu Emperor, took power in 1368 C.E. He founded the Ming Dynasty, famous for its achievements in the arts of ceramics and painting. The Ming emperors improved the wall with watchtowers and platforms. Most of the familiar images of the wall show Ming-era construction in the stone. Depending on how the wall is measured, it stretches somewhere between 4,000 and 5,500 kilometers (2,500 and 3,400 miles).
In the 17th century, the Manchu emperors extended Chinese rule into Inner Mongolia, making the wall less important as a defense. However, it has retained its importance as a symbol of Chinese identity and culture. Countless visitors view the wall every year. It may not be clearly visible from space, but it is considered “an absolute masterpiece” here on Earth.
To Build or Not to Build? That Was the Question
Whether to build the Great Wall or not was a hotly debated question for millennia in China.
- Pros: Supporters believed that building the Great Wall was the best way to establish Chinese sovereignty and defend against the north.
- Cons: Opponents, however, said that building the Wall would end up exhausting labor and monetary resources, and, even if the Wall was built, without continuously investing in soldiers guarding it, it was useless.
What Was the Great Wall of China Originally Built For?
To find out why the Great Wall was built, or, to be more specific, why the first prototype Great Wall was originally built, we need to look back at what happened before the 7th century BC.
In ancient Asia, the land was distinguished by two colors, green and yellow, divided by a “400-mm rainfall line” (north of which less than 400 mm, i.e. 16 inches, of precipitation fell per year).
The ‘green land’ in the south was fertile and suitable for cultivation, and agriculture was first developed there; while the ‘yellow land’ in the north and west was relatively barren and could only be used for nomadic pastoralism and animal husbandry.
During the Spring and Autumn Period (770–476 BC), private ownership and farming of land had already emerged south of the ‘rain line’. Whenever natural disasters occurred, herdsmen in the north would go south to rob the established farms.
The vassal states on the ‘rain line’ border of northern China urgently needed a complete defensive system to protect the land they had acquired. The earliest ‘Great Wall’ was born at that time to defend against opportunist plundering.
When and Why Did China Continue to Build the Great Wall?
According to historical records, over 20 vassal states of feudal dynasties built the Great Wall.
2,600 Years Ago — Walls Were Built Separately to Defend the Vassal States and North Nomads
Map of the Pre-Qin-Dynasty Great Walls
With the end of the Western Zhou Dynasty (1046–771 BC), ancient China entered into a period (770–221 BC) when more than 100 vassal states fought back and forth to expand their territory.
According to historical records, the Chu State first built a ‘Great Wall’ around 676 BC and it turned out to be quite effective in resisting invasions. Other states then began to build ‘Great Walls’ on the borders of their own territory. These Walls were more like dotted lines, scattered in all directions, ranging from several hundred to 2,000 meters (1.2 miles) long.
With different defensive aims, these Walls (known as Pre-Qin-Dynasty Great Walls) were roughly divided into two purposes during this period:
- The Southern Great Walls, built by the states of Chu, Qi, Han, Wei, etc. well south of China’s northern border, defended against invasion by neighboring states.
- The Northern Great Walls, built by the states of Qin, Zhao, and Yan, whose territories were contiguous to the earlier-mentioned northern nomads’, defended against occasional raids and looting.
From 221 BC: Partition Walls Pulled Down, and Border Walls Joined Together to Protect China’s North
Map of the Qin Dynasty Great WallsQin
You must have heard of the Terracotta Army. Its owner, Qin Shihuang, China’s First Emperor, united China in 221 BC and ordered the pulling down of the southern Great Walls, but he purposefully kept and linked the northern Walls built by the states of Qin, Zhao, and Yan.
Why did he do so? The Qin Empire was threatened by the Huns (the Mongol Empire of the time) in the north. In 215 BC, he sent general Meng Tian to build the Great Wall, using the basis of the northern states’ Great Walls to defend against the Huns.
The Great Wall linked today’s Gansu Province in the west to North Korea in the east and was amazingly consistent with the 400-mm-rainfall-line. Geographically and climatically, the Qin Great Wall established a dividing boundary between static farming and nomadic animal husbandry.
From 202 BC: To Promote Expansion and Protect the Silk Road
Map of the Han Dynasty Great Walls
With the ongoing wars by the end of the Qin Dynasty, the increasingly powerful Huns became a primary threat. In the early years of the Han Dynasty (206 BC – 220 AD), though the Great Wall was in disrepair, it did assist in blocking the Huns’ attacks.The Han Dynasty (206 BC – 220 AD) extended the Great Wall west to protect the Silk Road trade.
The Han empire was in its peak period during the reign of Emperor Han Wudi (ruled 141–87 BC). He started a few full-scale wars and finally defeated the Huns. For a solid defense, he ordered the rebuilding of the previous Qin Great Wall and the building of two new parallel Walls in today’s western Inner Mongolia. Meanwhile, he began to resettle Han residents in the north, carry out agricultural development, and station armies there for protection.
With the expansion and migration to the western regions, the Great Wall was then extended west through the Hexi Corridor (nowadays the Yumen Pass fort and the Dunhuang Great Wall Section in Gansu still survive), which also promoted the opening of the Silk Road.
The Han Great Wall was the longest Great Wall in history at over 10,000 km (6,200 mi), not only maintaining the territory of the Central Plains but also ensuring security along the Silk Road. Meanwhile, people moving to the northern and western regions for farmland exploitation, also promoted Chinese population migration and new local economies.
581–1271 AD: The Great Wall Was Strengthened in China’s Flourishing Dynasties
The following dynasties — Sui (581–618), Tang (618–907), and Song (960–1279) — rebuilt, modified, and extended the Great Wall to protect the Chinese Empire from northern invaders.
However, by 1271, the Mongolian Empire had defeated and subsumed the northern Song Dynasty forces, as well as the Jin Dynasty (1115–1234) and Western Xia Dynasty (1038 – 1227) in the north, making the Great Wall redundant during China’s the Mongol-led Yuan Dynasty era (1271–1368).
1368–1644 AD: The Great Wall Was Upgraded
Map of the Ming Dynasty Great Walls
- Most of today’s Great Wall was built or restored in the Ming Dynasty.
In order to consolidate their northern border against pressure from the Mongolian Tatars and Oirat tribes and later the Jurchen in the northeast, after reclaiming China from the Mongol-led Yuan Dynasty (1279–1368), the emperors of the Ming Dynasty (1368–1644) never stopped building the Great Wall.
The most well-known sections (Simatai, Mutianyu, Jinshanling, Badaling, etc.) were all built or strengthened by Qi Jiguang (1528–1588, a hero general who also saved China’s coastlands from Japanese pirates).
Although the Great Wall saw developments in the previous dynasties, the Ming Great Wall saw great upgrades in both its construction and military strategy.
The Ming Dynasty builders began to use bricks and tiles on a large scale and mixed the lime mortar with sticky rice pulp to make the wall sturdier and more durable. Combat modifications, such as gun holes, watch holes, and powerful artillery machines from Portugal, were installed on the Wall.
From 1644 AD: The Great Wall Was Built as the Country’s Boundary
The emperors of the Qing Dynasty (1644–1912) didn’t build the Great Wall and even forbade it: they were the Manchus, who the Great Wall was built to keep out!
Meanwhile, they believed that the only way to protect China was to gain international support, instead of border battles.