He is widely credited with transforming the Zulu from a small tribe into the beginnings of a nation-state that held sway over the large portion of Southern Africa that stretches between the Phongolo and Mzimkhulu rivers. His military prowess and destructiveness have been widely studied by modern scholarship. One "Encyclopædia Britannica" article (Macropaedia Article "Shaka" 1974 ed) asserts that he was something of a military genius for his reforms and innovations. Other writers take a more limited view of his achievements. Nevertheless, his statesmanship and vigour in assimilating some neighbours and ruling by proxy marks him as one of the greatest of the Zulu chieftains.