A compromise was reached that resulted in the adoption of a separate flag for the Union in late 1927, and the design was first hoisted on 31 May 1928. The design was based on the so-called Van Riebeeck flag or Prinsevlag ("Prince's flag" in Afrikaans) which was originally the Dutch flag, and consisted of orange, white, and blue horizontal stripes. A version of this flag was used as the flag of the Dutch East India Company at the Cape (with the VOC logo in the centre) from 1652 until 1795. The South African addition to the design was three smaller flags centred in the white stripe. The smaller flags were the Union Jack (mirrored) towards the hoist, the flag of the Orange Free State (mirrored) hanging vertically in the middle and the Transvaal Vierkleur towards the fly.
The choice of the Prinsevlag as the basis upon which to design the South African flag had more to do with compromise than Afrikaner political desires, as the Prinsevlag was believed to be the first flag hoisted on South African soil and was politically neutral as it was no longer the national flag of any nation. A further element of this compromise was that the Union Flag would continue to fly alongside the new South African national flag over official buildings. This state of duality continued until 1957 when the Union Flag lost its official status as per an Act of Parliament; the Red Ensign had lost its status as South Africa's merchant flag in 1951.
Following a referendum, the country became a republic on 31 May 1961, but the design of the flag remained unchanged. However, there was intense pressure to change the flag, particularly from Afrikaners who resented the fact that the Union Flag was a part of the flag.