[andsoitis]

> Most of the economy back then was non-monetary.

In 600 BCE, Lydia's King Alyattes minted what is believed to be the first official currency, the Lydian stater. The coins were made from electrum, a mixture of silver and gold that occurs naturally, and the coins were stamped with pictures that acted as denominations.

https://www.investopedia.com/articles/07/roots_of_money.asp

But also note that physical currency is not necessary for “money”. Money has been around for about 5000 years, ridding us from barter.