The famous ruler responsible for building the Great Wall of China is Qin Shi Huang, the first Emperor of China. He unified various warring states in 221 BCE, and his reign marked the beginning of the Qin Dynasty. To protect his newly unified empire from invasions by nomadic tribes, he initiated large-scale construction of defensive walls, which eventually became what we know today as the Great Wall. This monumental project not only served military purposes but also aimed to consolidate the empire’s territory and enhance command over trade routes.