21 February 1803
In terms of the Treaty of Amiens, signed in 1802 (between England and France), the British officially returned the Cape Colony to the Netherlands on 21 February 1803. It was then renamed the Batavian Republic and the flag of the Batavian Republic was hoisted on the Castle. The Dutch only governed for three years (1803-1806), but their enlightened administration of the Cape was a great improvement upon the rule of the Dutch East India Company, which had lasted from 1652 to 1795. Commissioner-General J.A. de Mist and the Governor of the Cape of Good Hope, Lieutenant-General J.W. Janssens, sponsored development and reforms. In short the colonial history of the Cape of Good Hope from its first occupation in 1652 is as follows: Dutch rule in the cape colony 1652 - 1795 British occupation 1795 - 1803 Return to Dutch rule 1803 - 1806 Second British occupation 1806
References

Potgieter, D.J. et al. (eds)(1970). Standard Encyclopaedia of Southern Africa, Cape Town: NASOU, v. p. 202 & 516|Kruger, D.W. (ed)(1979). Geskiedenis van Suid-Afrika; verwerk en bygewerk deur D.W. Kruger; 3de bygewerkte uitg, Goodwood, Cape Town: NASOU, p. 140.|Howcroft, P. (undated). South Africa Encyclopaedia: Prehistory to the year 2000, unpublished papers donated to SA History Online