I heard a very small portion of an NPR program about 1800's mercantile agencies and found it very interesting, but I had to get out of the car and didn't catch much.

I heard a little bit about how they were the origin of the credit report in that people used them to ensure they weren't going into business with people who had issues repaying their debts.

You would walk into their office and they would look up whoever you were interested in and they would read out loud what they had discovered about the person. You weren't allowed to take or copy the page but you could take notes while they read it. You also weren't allowed to look yourself up. That's all I managed to catch.

I'm particularly interested in the people who did the investigating themselves, and what, if anything, people could do if false things were written about them. From a historical context these were still pretty recent, how far back in history do we have examples of this kind of thing?