If an employee wants to achieve something, he would better not stand alone. People already realized this in the 18th century. When the industial revolution forced women, children, rural workers and immigrants to work in groups in terrible circumstances, the need for a labour union association grew.
At first, this was prohibited by the law because the employer, who wanted to exploit their workers to maximize their benefit, feared insurrection and rise in costs. However, the chance to get punished (in some counties, there even was a risk to be executed) did not stop the attempt to assemble.
Ann-sophie Buyse
http://www.encyclopedia.com/doc/1E1-union-la.html
http://en.wikipedia.org/wiki/Trade_union
http://ezinearticles.com/?The-History-of-Labor-Unions&id=1119684