HUAI-NAN Tzu (d. 122 B.c.) was the most prominent Taoist philosopher between ancient Taoism of the fourth century B.C. and Neo-Taoism of the third and fourth centuries A.D. His originality is negligible, but he maintained Taoism at the time when Confucianism had just assumed the dominant and exclusive role in government as well as in the realm of thought. Although his ideas are no more than reiteration and elaboration of Lao Tzu and Chuang Tzu, at least he kept the fire of Taoism burning and helped to make possible the emergence of Neo-Taoism. Because of his essentially rational approach to metaphysics and cosmogony, it may be said that he indirectly, at least, prepared for that rationalistic critic Wang Chung (27-100?). His name was Liu An. As Prince of Huai-nan, he had thousands of scholars under his patronage. He plotted rebellion, failed, and committed suicide.
Source : Wing-Tsit Chan, in Chinese Philosophy