24 August 1896
The Johannesburg suburb of Mayfair was laid out the farm Langlaagte No.258, the farm on which gold was discovered in the late 1800s. The mineral rights of Langlaagte were bought by J.B Robinson in 1886, and the first plots were sold on 24 August 1896, after the land was surveyed by Government surveyor M.C. Vos. The suburb is thought to have been named after the well-known London district.
References

Meiring,H, Van Der Waal, G-m., and Jonker, A., "Early Johannesburg, its buildings and its people", (early Johannesberg), pp 100|

Potgieter, D.J. et al. (eds)(1970) Standard Encyclopaedia of Southern Africa, NASOU: Cape Town, v. 7, p. 258.