Elizabeth Chadwick's Medieval Mondays on her blog Living the History has an uh, interesting entry for this week. . . (sorry, folks, I know it's Tuesday and all that!). It's about moneyers(or minters, as they were sometimes called). Some background: Every town of any size, by law, had a mint where coins -- English silver pennies -- were minted and stamped with a design approved by the king. These coins circulated for several years(I think it was three), and then, again by order of the reigning king, were withdrawn, and new silver coins, with a new stamp, were issued. People with the old coins then had to pay a visit to the town mint(in some really large towns there were apparently two or three of them), turn the old coins in, whereupon they would be melted down and new coins made with the new official stamp. The moneyer/minter charged you a fee for this. This was how minters made their money, and some of them became quite rich and important.
Unfortunately, the system was subject to abuse, and it was not unknown for moneyers to cheat. The king, or at least what passed for his bureaucracy, knew, or eventually found out, and laws kept getting passed. This didn't necessarily stop anybody, so the kings had to periodically rein in the moneyers.
So here is what one of the current Medieval Monday posts has to say about this situation. After I read about this solution, I began to wonder whether someone, somewhere, could channel King Henry I to deal with the financial shenanigans of some modern bankers and Wall Street fat cat types. Nah, I decided. That would be too big a job even for Henry I!