Early Chinese rulers established what by conquering and uniting kingdoms under the rule of one emperor? from 624 to the early 1100s, the who ruled over a golden age of prosperity before the Mongols invaded?

Early Chinese rulers established a centralized imperial government by conquering and uniting kingdoms under the rule of one emperor. From 624 to the early 1100s, the Tang Dynasty ruled over a golden age of prosperity before the Mongols invaded.