 The earliest evidence for acupuncture in this sense dates to the second or first century BCE.The "Yellow Emperor's Inner Canon (Huangdi Nei Jing)", the oldest received work of Chinese medical theory, was compiled during the Han dynasty around the 1st century BCE on the basis of shorter texts from different medical lineages.Written in the form of dialogues between the legendary Yellow Emperor and his ministers, it offers explanations on the relation between humans, their environment, and the cosmos, on the contents of the body, on human vitality and pathology, on the symptoms of illness, and on how to make diagnostic and therapeutic decisions in light of all these factors.