Who am I thinking of? The ruler (maybe around 500 BC?) who embraced all cultures and developed a very powerful and diverse nation?

by Agemrepus

I remember learning about eastern civilizations in school, and one particular leader always stuck out to me, but I cannot remember his name.

He was known for embracing other cultures, and even offering freedom to the prisoners of war, as long as they promised to join his nation and remain loyal to him. He always seemed so cool to me, and I want to learn more but don't know where to look for more info!

Bj231