The era of Emperor Wu of the Han Dynasty is a heroic era in the cultural history of China, and Emperor Wu of the Han Dynasty is also a historical hero who has created outstanding achievements. Xia Cengyou, a modern scholar, said in his book The Ancient History of China that some emperors of past dynasties were "once emperors", such as Emperor Gaozu, but they were "emperors of twenty-four dynasties in China", such as Emperor Wudi. Emperor Wu of the Han Dynasty is said to be "the emperor of the 24th dynasty in China" because the historical road he confirmed, the cultural atmosphere he created, the political system he created and the national territory he established had a very long-term impact on the history of China. Xu Zhuoyun, a historian, wrote in the preface of the book "Emperor Wu of the Han Dynasty made history" that the decision-making of historical figures can "finally choose the direction of evolution among various possibilities". He said, "once the direction is determined, history cannot turn back, so future generations can only accept this fact and make the next choice." The so-called Emperor Wu of the Han Dynasty "made more achievements than a hundred kings" and "was the emperor of the 24th dynasty in China" because the direction he chose had a prescriptive effect on later generations, and people "had to accept this fact". The determination of this "direction" is manifested in the occurrence and handling of events and the formulation and implementation of policies. There were many important measures in the era of Emperor Wu of the Han Dynasty, all of which, as Lao Gan, a great historian of Qin and Han Dynasties, said, reflected the "great wisdom and great decision" of this historical figure.