the big question

My big question is, how has the idea of money changed over time? I chose this topic because i find it very interesting, and i'd like to learn more about it. I want to know why people stopped using valuables to barter, and switched to paper, and why now we are doing a similar thing, moving from paper to almost all digital money. also, im considering a business career and i think it would be a good idea to see the origins of money and how it came to be. I want to know when the first banks started, and who came up with the idea, and when investing started and why it started. As a side topic, i want to talk about wealth and what it means to be wealthy, and how that idea has changed over time. Wealth today is not the same as wealth a long time ago because we value different things than they did.