The generally accepted history of the martial art of Wing Chun is as follows. The legend of Yim Wing Chun is regarded as a "legend" as there is no verifiable proof for it.
In medieval China, there existed a Buddhist temple called Siu Lum (Shaolin), which was infamous for the martial arts skills of the Buddhist monks (and nuns) who lived and trained there. Around the end of the Seventeenth Century, the then Manchu Emperor of China, K'anghsi, feeling threatened by the thought of there being such highly trained warriors who were not under his control, ordered the temple to be destroyed. As a result of this attack, the temple was raised to the ground. Only five of the elders of the temple survived this attack, four monks and a nun. The nun's name was Ng Mui ("Plum Flower").
Following the attack, Ng Mui fled the temple. Whilst living out in the wilderness, she considered the nature of the martial arts she had trained at Siu Lum, and thought about how the whole martial arts training process could be made simpler and more streamlined. One day whilst walking in the woods, she happened to witness a fight between a snake and a crane. As she observed the animals, she was inspired by the tactics being used by the two creatures. Neither animal made any unnecessary movements, the snake used swift direct attacks, the bird simultaneously used its wing to protect itself whilst counter-striking with its beak. Both creatures stood their ground, while attempting to find the weakness in their opponent's position. Ng Mui was inspired with what the animals were doing. Instead of trying to copy their actual movements, which would be unnatural for a human, she implemented the ideas she had witnessed.
She settled near a small village near by. In the market place there, there was a bean curd seller, Yim Yee, whom Ng Mui often visited. He had a daughter called Yim Wing Chun. She had attracted the unwanted attentions of the local warlord.
The bean curd seller, knowing of Ng Mui's martial arts skills, asked her for her help. She agreed to teach Yim Wing Chun the new simplified approach to fighting that she had been working on. After months of intense training, the warlord returned to the village for Yim Wing Chun. This time, Yim Wing Chun was ready for him. She challenged the warlord to a fight, and soundly beat him.
Now that Yim Wing Chun was rid of the warlord, she was free to marry her fiance, Leung Bok Chau. The couple continued to train and refine the new style further. In honour of his wife, Leung Bok Chau named the new martial art Wing Chun.
The art was then passed down through many generations. Leung Bok Chau passed on his knowledge to a herbalist called, Leung Lan Kwai. He in turn taught a student, Wong Wah Bo. He was a member of a Peking opera troupe, whom travelled about China on the waterways via the junks. During his travels, he met and befriended another martial artist Leung Yee Tai. Leung Yee Tai had learnt the art of pole fighting from a former senior abbot from Shaolin, one of the elders who had survived the attack on Shaolin along with Ng Mui. Wong Wah Bo and Leung Yee Tai shared their knowledge of martial arts, and so the Luk Dim Boon Kwun (pole form) became a part of the system.
Leung Yee Tai then taught Leung Jan. He is the first Wing Chun ancestor who's existence is general considered to be verifiable, and also the subject of the film "Prodigal Son". His final student was Chan Wah Shun (known as the "money changer"). His final student was a nine year old boy, who would eventually become the founding father of most modern Wing Chun as it is known today. His name was Yip Man. Si Jo Yip Man taught Wing Chun prolifically in Hong Kong during the 1950's and 1960's. Amongst the many students that he taught, was the famous martial arts film star Bruce Lee, and my Si Gung, his eldest son sifu Yip Chun.
The above history, prior to Leung Jan, is very questionable, if only because there appears to be only about 5 generation spanning about 200 years. None the less, those who practice Wing Chun today do owe a debt of gratitude to those who developed the art before us, who ever they were.