Johanna and Hester Cornelius were brought up in the Western Transvaal in an Afrikaner family. Their family was very nationalistic, with both their father and grandfather fighting in the Anglo Boer War, their mother being held in a concentration camp during the war and their father joining the 1914 Afrikaner Rebellion.
In 1920 Johanna and Hester, were forced to go and look for work away from the farm, and in 1930 they both began work in a clothing factory. At this time the white workers were busy forming the Garment Worker’s Union (GWU) with the help of Emil Solomon Sachs. Johanna quickly got involved in the Union and was arrested in 1932 during a strike. On her release she gave a speech calling on workers to demand a living wage and freedom- just as people had done with the Great Trek and with the Anglo Boer War. This shows how she joined nationalism together with the class struggle rather than with the national struggle.
The GWU strike was a failure, and workers were forced to return to work. The Union however grew stronger over the years. Many workers also got involved in the organisation of the Union, such as Johanna and Hester. In 1933 Johanna spent a month in the Soviet Union as a trade union delegate, and in 1934 became a full time organiser. In 1935 she was elected president for a two-year period. Hester was elected to the Union’s executive in 1934.
In 1938 Johanna was accused of being a communist accomplice of Sachs and for spending all her time organising blacks. The strong structure of the union enabled them to ward off attacks, and Hester spent time defending the union by organising cultural events using Afrikaner symbols.
The sisters did not limit themselves to the GWU or to the Transvaal, and were also involved in other activities across South Africa. In 1952, when Sachs was banned, Johanna became general secretary of the GWU, a position she kept until her death in 1974. Hester became national organiser in the 1960s. These were difficult times with wages dropping and more black workers entering the clothing factories. Black workers were allowed to be part of the GWU, but as a separate branch as the government did not allow racially mixed unions. This undermined wage negotiations and brought criticism from the left-wing unions such as the South African Congress of Trade Unions (SACTU).