Mythical legend of taiji origin

Legend One:  The Taoist Cheng San Fung, created Taiji Quan from observing the struggle between a crane and a snake.  He noticed that the soft movement of the snake was very effective in warding off the sharp strike of the crane's beak.  Hence, he realized that Taoist principle of the soft conquering the hard, the yielding and fluid movement of Taiji expresses the grace of this reeling silk motion..
Legend Two:  The Wudang monastery was besieged by bandits, Cheng San Fung, ( Ming dynasty 1600 AD) had an visionary dream in which the immortal warrior taught him the a combative form, Taiji quan.  After one night of such dreaming, he used this Taiji form to defeat the bands of bandits .
Legend Three:  A retired Ming general of the Chan village created the Taiji Quan.based on a late Ming martial manual, The Art of War.  This claim fits very well to the Communist Chinese government's ideology of giving the taiji a proletarian pedigree of being a product of the people and not some decadent feudalistic Taoist alchemy.

Historical truth...
The truth of the origin of taiji will never be certain. However, one can deduce from the above legends an overall ontological development of taiji. Most likely, proto-taiji existed as a movement cult of the Neidan, inner alchemy of circulating the qi. Then this is absorbed by later masters--noticeably the Chan villager who had intimate knowledge of the taoist alchemical cultivation. He combined his knowledge of Shaolin hard martial practice with this softer movement of taiji. In the Chan village, the taiji form is simply called the first set. Hence, the first set of movement is gentle in order to warm up the limbs and sinews. The Chan 2nd set, Cannon Fist, is hard and fast with explosive punching and kicking. An outside observer will be hard to distinguish the 2nd set from the more traditional Shaolin fist form.