Final answer:
The Qin Dynasty brought the first great period of Chinese unity and the first emperor.
Step-by-step explanation:
The first great period of Chinese unity and the first emperor came with the Qin Dynasty. The Qin state, led by King Ying Zheng, conquered and united several states, establishing the Qin Dynasty as China's first imperial dynasty. Under the rule of Emperor Qin Shi Huang, the dynasty brought stability through standardized weights and measures, language, and laws. The Qin Dynasty lasted from 221 BCE to 206 BCE.