Which is the oldest historical form of money?

Could you please elaborate on which historical form of money is considered to be the oldest? Are we referring to physical forms of currency like shells, precious metals, or coins? Or is there a more ancient system of exchange that predates these? I'm curious to know the specifics behind the oldest form of money and how it was used throughout history. Additionally, how has the evolution of money impacted our current financial systems and the rise of cryptocurrencies?