11 October 1663
On this day Sergeant Jonas de la Guerre left the Cape to venture north in search for the "great river that flowed east to west" and to "investigate trade opportunities". He was acting according to the instructions of Zacharias Wagenaer, Commander at the Cape. De la Guerre went on this  expedition in 1663 with Pieter van Meerhof as second in command, along with 14 European volunteers and three 'Hottentots'. They trekked together by ox-wagon to the Olifants River, where they left the wagon behind and continued with pack oxen. It is assumed that De la Guerre probably progressed to within eight to ten days journey of the 'great river', namely the Orange River, but was forced to turn back due to harsh terrain. When they returned to their abandoned wagons, they found that their wagon had been destroyed and their gunpowder stolen, apparently by the Namaquas. The group was then forced to eat their oxen and walk back, or face death. They eventually returned to the Cape on 22 January 1664, in an apparently "deplorable state”. According to other sources, de la Guerre also left the Cape in search of Monomotapa, a legendary city. This area was situated in Zimbabwe, from the Zambezi to the Indian Ocean, and was rumoured to be rich in gold. However, this empire had disintegrated due to Portuguese exploitation, and was only actually discovered by an expedition from the south almost 200 years later.
References

Potgieter, D.J. et al. (eds) (1971). Standard Encyclopaedia of Southern Africa, Cape Town: NASOU, v. 3, p. 626; vol. 7 p.517|

Wallis, F. (2000) Nuusdagboek: feite en fratse oor 1000 jaar, Kaapstad: Human & Rousseau|

Fleminger, D. (2008) The Richtersveld Cultural and Botanical Landscape: Including Namaqualand (Southbound) p.60