Yeah, money. Wealth is a reflection of specialisation in society. As the roles get complex, its often required for a common and standardised means of exchange; that correctly values the services given, and rewards to be received in return. For a long time in the history of humans, the unit of wealth was something valuable, collected farm produce, or special pottery or maybe even rare metals. Even our mythos, often speak of the horses and cows being used as a unit of wealth. All of these related to something that was physical, useful and limited. But the potential of wealth goes beyond the basics of security and exchange, relating to the abstract concept of power and dominance. Over time this soft control that comes along with wealth has gained more and more importance. And with power comes, the insatiable lust to remain powerful. Governments and kingdoms attempting to accumulate the methods of wealth generation, keeping it, out of reach for the public. And social hierarchies came in