The old Daoist priest Zhang-Sang-Feng had a dream on the holy mountain Wu-Dang, in which the legendary emperor Xuan-Wu appeared and taught him Tai Chi Chuan. Due to this Tai Chi Chuan would be a present of the Gods.
More probable is the tradition that the family Chen coming from the Chinese province of He-Nan was responsable for the development and the proliferation of Tai Chi Chuan, which possessed other forms at this time as today.
The Chang-Quan-style (long boxing) was named according to the Chinese river Chang-Jiang (Yangtsekiang), because it appeared to have the same movements as the river. The Chang-Quan-style consists of thirteen basic forms, the reason why it's also simply called "Thirteen Forms" (Shi-Shan-Shi).
The Thirteen-Form-Style consists of eight basic forms for the hands and five basic forms for the body. This style shows great resemblances to the martial art of the general Qi-Ji-Guang (1528-1587 n.Chr.) who lived during the Ming-dynasty. The general developed a new style of fighting by selecting the best forms out of sixteen different boxing schools (families) which he changed or linked together. He presented his results in the book Quan-Jing, the book of boxing. It is supposed that Tai Chi Chuan was influenced strongly by the style of general Qi-Ji-Guang.
The characteristics of this new style of boxing were described by the martial-arts master Wang-Zong-Yue (1736-1795 n.Chr.) in his book Tai-Ji-Quan Lun (essay on Tai-Ji-Quan.) Remarkable is, that he brought the philosophy of Yin and Yang in close relation to the new style of boxing. At the same time he introduced the name Tai Chi Chuan, or also Tai-Ji-Quan. The time when the Chen-family took over this term for the first time , is not bequeathed. however it is known, that the new martial-art Tai Chi Chuan starting in the province of He-Nan from 1850 onwards quickly spread over China.
In the 19th century Tai Chi Chuan underwent some fundamental changes. The powerful and explosive elements were eliminated in favour of smooth and aesthetic movements, the result of which is today's Tai Chi Chuan. Because of its relaxed, soft and round movements Tai Chi Chuan wasn't anymore only for athletes but could be practiced from now on by children, sick and elder people as well. This lead to the fact that this martial-art got into the focus of medecine due to its positive effects on health and was praticed to prevent illness.