Which emperor ordered the major unification of walls that became China’s Great Wall?

Qin Shi Huang ordered the major unification of earlier defensive walls that became part of China’s Great Wall. He founded the Qin dynasty and unified much of China in 221 BCE.

Earlier states had built walls along northern frontiers, especially during the Warring States period. After conquering rival kingdoms, Qin Shi Huang connected and extended some of these defenses under the direction of generals such as Meng Tian, partly to resist raids by northern nomadic groups.

The Qin-era structures were not the same continuous masonry monument most visitors see today. Many were made largely from rammed earth and have since eroded. Major surviving sections near Beijing were built or rebuilt much later, especially during the Ming dynasty from the fourteenth to seventeenth centuries.

The Great Wall is therefore a network of fortifications created over many centuries, not a single wall built by one ruler. Its total length, including trenches and natural barriers, is measured in tens of thousands of kilometres.