The best way to approach the Northern Cape frontier zone is via an understanding of the significance of the frontier in South African history. A further adaptation of the frontier thesis occurred when English speaking liberal historians realized that Leo Fouche's vision of the frontier's significance, when grafted on to the Great Trek, tended to valorise the white racism of modern South Africa. Martin Legassick's paper was inspired by a predominantly Marxist view of history and became an important manifesto for a new, radical or revisionist approach to the South African past. Legassick's thesis focused mainly on the Griqua, the Sotho-Tswana and the missionaries of the northern frontier zone between the years 1780 to 1840. The American frontier was one of exclusion and near extermination of the Indian whereas the South African frontier was one of inclusion as well as exclusion.