28 May 1900
At the begging of May 1900, the British Army, under Field Marshal Lord Roberts, launched an attack on the Orange Free State. President M T Steyn and General C R de Wet of the Orange Free State (Boer Republic) failed to defend their capital town Bloemfontein. The British advancement from the Free State capital was delayed for six weeks to enable Roberts to rest his troops and horses. Shortly after his entry into Bloemfontein, Roberts announced the annexation of the Orange Free State. He also promised burghers who surrendered voluntarily that they would be allowed to return to their farms. The new colony was known as the Orange River Colony.
References

 Goldstein, E.,(2005), Wars and Peace Treaties: 1816-1991,(New York),pp 145-146|

Dupont, J., (2001), The Common Law Abroad : Constitutional and Legal Legacy of the British Empire,(United State of America), pp 1032-1034