1644 – The Largest Coin

Hah, came to post the same link. Seriously. A 20kg copper plate is not exactly pocket change, but it doesn't hold a candle to 4 metric tons.

> The ownership of a large stone, which would be too difficult to move, was established by its history as recorded in oral tradition, rather than by its location. Appending a transfer to the oral history of the stone thus effected a change of ownership

So, like an NFT before they were cool?

Binary wouldn't be half bad: halves, quarters, eighths, sixteenths and thirty seconds of a pound.