There is a very famous traditional Chinese story that has a close connection to the Dragon Boat Festival. Once upon a time on E-Mei mountain there lived two snake spirits, White Snake and Green Snake. These snakes, being magical, turned themselves into beautiful maidens and set off on a journey to the West Lake of Hang Zhou.
When they arrived at West Lake they met a man named Xu Xian. White Snake quickly fell in love with Xu Xian and they were soon married. A Buddhist monk, named Fa Hai, warned Xu Xian of his wife's deceptive appearance and suggested to him a plan.
On the day of the Dragon Boat Festival White Snake wished to stay home so as to avoid the Ay Tsao, used for protection from spirits, hanging on the doors of people's houses. Her husband prepared, according to Fa Hai's instruction, some realgar wine, as this was a tradition during the Dragon boat festival. White Snake, thinking her magic would protect her from the effects of the realgar wine accepted a cup. After she drank the wine she became very ill and was barely able to get to her bed.When her husband came to her side, he found not his wife but a huge white snake. So great was Xu Xian's shock that he fell to the floor dead.
After recovering from the realgar wine and regaining her human form, White Snake was grief-stricken to find her husband dead. She set off on a journey to obtain a potent medicinal herb, which could revive her husband. After returning and reviving her husband with the medicine, she explained to Xu Xian that the white snake he saw was actually a dragon and that this vision was indeed a very good omen. Xu Xian's fears were put to rest for the moment by his wife's fanciful story...