The Free Trade Unions (, SSS) was a central

trade union A trade union (British English) or labor union (American English), often simply referred to as a union, is an organization of workers whose purpose is to maintain or improve the conditions of their employment, such as attaining better wages ...

organization in

Bulgaria Bulgaria, officially the Republic of Bulgaria, is a country in Southeast Europe. It is situated on the eastern portion of the Balkans directly south of the Danube river and west of the Black Sea. Bulgaria is bordered by Greece and Turkey t ...

. SSS was founded in August 1904, and was politically tied to the Bulgarian Social Democratic Workers Party (''Obedinena''). As of 1904, SSS had 1,188 members. By 1907 the membership had risen to 1,884.Linden, Marcel van der, and Jürgen Rojahn.
The Formation of Labour Movements, 1870-1914: An International Perspective. Contributions to the history of labour and society, v. 2
'.

Leiden Leiden ( ; ; in English language, English and Archaism, archaic Dutch language, Dutch also Leyden) is a List of cities in the Netherlands by province, city and List of municipalities of the Netherlands, municipality in the Provinces of the Nethe ...

: E.J. Brill, 1990. p. 410

References

Trade unions in Bulgaria 1904 establishments in Bulgaria Trade unions established in 1904 {{Trade-union-stub