The topic of early iron-metallurgy in sub-Saharan Africa encompasses both studies of the technology and archaeology of indigenous iron-production. Some recent studies date the inception of iron metallurgy in Africa between 3,000 and 2,500 BCE. Evidence exists for earlier iron metallurgy in parts of Nigeria, Cameroon, and Central Africa, possibly from as early as around 2,000 BCE.Some evidence from historical linguistics suggests that the Nok culture of Nigeria may have practiced iron smelting from as early as 1000 BCE;The nearby Djenné-Djenno culture of the Niger Valley in Mali shows evidence of iron production from c. 250 BCE. The Bantu expansion spread the technology to Eastern and Southern Africa during c. 500 BCE to 400 CE, as shown in the Urewe cultureof the Lake Victoria region.