7 January 1919
The Industrial and Commercial Union later renamed the Industrial and Commercial Workers Union (ICU) was founded by Clements Kadalie, a young Nyassalander who spoke no Black South African language but used English to spread the message of worker unity. Formed in the stormy years after World War I with a membership of only twenty-four, the Industrial and Commercial Union made its first powerful impact when the Cape Town dock workers went on strike. From small beginnings as a union of dock workers it quickly spread across the country, enrolling about 100,000 members, and pushed the more conservative African National Congress (ANC) into the background during the 1920s. This provoked a serious backlash by the White government and politicians, who feared a national uprising and caused them to proceed carefully in their relations with the ICU.
References

Karis, T. & Carter, G.M. (eds.) (1973). From Protest to Challenge: a documentary history of African politics in South Africa. Stanford: Hoover Institution, v. 1, p.154-155.|Potgieter, D.J. et al. (eds) (1970). Standard Encyclopaedia of Southern Africa, Cape Town: NASOU, v. 1, p. 60.|Reader's Digest. (1988). Illustrated History of South Africa: the real story, New York: Reader's Digest Association, pp. 310; 320.