Africa" from "a ritualised exchange of taunts with minimal loss of life into a true method of subjugation by wholesale slaughter." Others dispute this characterization (see Scholarship section below). A number of writers focus on Shaka's military innovations such as the iklwa – the Zulu thrusting spear, and the "buffalo horns" formation. This combination has been compared to the standardisation implemented by the reorganised Roman legions under Marius. Combined with Shaka's "buffalo horns" attack formation for surrounding and annihilating enemy forces, the Zulu combination of iklwa and shield—similar to the Roman legionaries' use of gladius and scutum—was devastating. By the time of Shaka's assassination in 1828, it had made the Zulu kingdom the greatest power in southern Africa and a force to be reckoned with, even against Britain's modern army in 1879. Much controversy still surrounds the character, methods and activities of the Zulu king. From a military standpoint, historian John Keegan notes exaggerations and myths that surround Shaka, but nevertheless maintains: As a borrower, not an innovator Some scholars hold that popular depictions of Shaka as a suddenly appearing genius creating innovation are overstated, and that to the contrary, Shaka was a borrower and imitator of indigenous methods, customs and even ruler-lineages already in place. They also argue that Shaka's line was relatively short-lived and receives undue attention, compared to other, longer established lines and rulers in the region. Shaka's triumphs did not succeed in obliterating or diminishing the memories of his better-born rivals. The hypothesis that several states of a new kind arose about the same time does not take account of the contrast between the short line of Shaka and the long pedigrees of his most important opponents – especially the coalition grouped around his deadly enemy Zwide (d. 1822). The founders of the states which Omer-Cooper called "Zulu-type states," including the Ndebele, the Gasa, the Ngoni, and the Swazi had all been closely associated with Zwide. Instead of hypothesizing that they all chose to imitate Shaka, it is easier to imagine that he modeled his state on theirs. And as they stemmed from ancient families it is entirely possible that states of that type existed in a more remote past. Soga and Bryant related each of them to a larger grouping they called Mho. Scholarship Biographical sources Scholarship in recent years has revised views of the sources on Shaka's reign. The earliest are two eyewitness accounts