https://en.wikipedia.org/wiki/First_International

"The International Workingmen's Association (IWA), commonly known as the First International [...] was founded in 1864 [...] The preparatory Address of English to French Workmen, drafted by trade union leader George Odger, articulated the need for international cooperation to prevent the importation of foreign workers to break strikes:

A fraternity of peoples is highly necessary for the cause of labour, for we find that whenever we attempt to better our social condition by reducing the hours of toil, or by raising the price of labour, our employers threaten us with bringing over Frenchmen, Germans, Belgians and others to do our work at a reduced rate of wages [...]"