Traditionally, the groups characterized as untouchable were those whose occupations and habits of life involved ritually polluting activities, of which the most important were (1) taking life for a living, a category that included, for example, fishermen, (2) killing or disposing of dead cattle or working with their hides for a living, (3) pursuing activities that brought the participant into contact with emissions of the human body, such as feces, urine, sweat, and spittle, a category that included such occupational groups as sweepers and washermen, and (4) eating the flesh of cattle or of domestic pigs and chickens, a category into which most of the indigenous tribes of India fell.
One of the things that gave the Kingdom of Ghana a military advantage over its neighbors was its use of iron to make weapons. Many other people in the area still were using wooden weapons.