The Qin Dynasty is known for having unified most of what became known as China under one leader. This leader, Qin Shihuangdi, defeated the other warring states to consolidate power. The name "Qin," which is pronounced as "chin," is the source of the modern name "China."
Qin Shihuangdi developed an administrative structure for the entire country, and he also regularized weights, measurements, currency and script throughout the entirety of his domain, explains About.com. This gave the region a uniform character that bound the people together as a unified polity. He also began the process of creating the Great Wall of China by unifying a number of border walls into one impressive barricade against invasion. Qin Shihuangdi's dynasty was not stable, though, and four years after he died in 210 B.C., his unified China was once again split into warring states.