Who taught your teacher of Wing Chun and from there who taught the teacher of your teacher and so on.
Some lineages for Wing Chun are listed in this website:
http://www.wcarchive.com/html/sifus/wing-chun-sifus-by-lineage.htm
Also for example the lineage of Ip man: http://en.wikipedia.org/wiki/Yip_Man
Ng Mui (one of the Five Elders of Shaolin Monastery)
Yim Wing-chun (taught Wing Chun by Ng for self-defence)[citation needed]
Leung Bok-chau (Yim's husband)
Leung Lan-kwai
Wong Wah-bo (taught the pole form by Leung Yee-tai)
Leung Yee-tai (added his pole form to the system he learned from Wong)
Leung Jan (also taught his son Leung Bik)
Chan Wah-shun
Yip Man
Some lineages for Wing Chun are listed in this website:
http://www.wcarchive.com/html/sifus/wing-chun-sifus-by-lineage.htm
Also for example the lineage of Ip man: http://en.wikipedia.org/wiki/Yip_Man
Ng Mui (one of the Five Elders of Shaolin Monastery)
Yim Wing-chun (taught Wing Chun by Ng for self-defence)[citation needed]
Leung Bok-chau (Yim's husband)
Leung Lan-kwai
Wong Wah-bo (taught the pole form by Leung Yee-tai)
Leung Yee-tai (added his pole form to the system he learned from Wong)
Leung Jan (also taught his son Leung Bik)
Chan Wah-shun
Yip Man