In africa, iron was the most important thing that they had ever discover. It was important, because they used it for many things. For example, they used it for trading. Iron was most needed in Rome. As a result, this helped the African's with their trading system. So this was one of the most important things that they develpoed.
I believe that iron changed many of the African's lives. If they wouldn't have found iron, then the African's might have suffered many things. For example they might have suffered attacks, in need of resources, cloth, etc. This is why whoever discovered iron should be thanked.