The main builder of the Great Wall of China was the first emperor, Qin Shi Huang (around 221-207 BCE). He connected existing walls that had been built by various states into one massive defensive system. After his death, many subsequent dynasties added and improved upon this structure. During the Ming Dynasty (1368-1644), the most significant expansions and additions to the wall were made. This included the strengthening and rebuilding of existing walls, as well as extending the existing walls and adding more fortifications. The Ming emperors personally ordered and directed the construction, making them the most important builders of the Great Wall of China.