1 · Sumer, 3200 BCE – Bread as the first ledger entryLong before coins, Mesopotamian city-states tracked grain, the staple for bread, as the unit of account. Farmers delivered barley to temple granaries; scribes pressed tiny clay tokens (cones for wheat, spheres for barley) into wet tablets to record deposits. Those imprints acted like transferable receipts. A laborer could hand his clay tablet to a merchant in exchange for bread or beer. Value lived in the promise of grain, secured by the te...