Peter the Great; he ruled over Russia. His biggest accomplishments are making the country much bigger than it was, and the reformation that took place when he modernized and westernized the country.
Ivan the Terrible; he ruled over Russia. He conquered large territories, mostly in Central Asia and Siberia, and he also reformed the country by making it from a medieval country to an empire.
Catherine II; she ruled over Russia. Her biggest accomplishments are making the Russian Empire much bigger than what it was, and gaining a status and recognition as one of the European superpowers.
With the ability to forge iron tools, farming tools were more effective and provided a greater production and effectiveness. More food produced means that more people are able to be fed and consequently establish and work in the land. With a higher population and food cap, West Africa settlements were able to grow.
