I yesterday ran across an interesting speech by Greenspan illuminating the history of U.S. banking. From 1837 to 1863, the United States did not have a central bank, and it was relatively easy to register as a bank and issue money.

I found the following part of his speech remarkable:
While free banking was not actually as free as commonly perceived, it also was not nearly as unstable. The perception of the free banking era as an era of "wildcat" banking marked by financial instability and, in particular, by widespread significant losses to noteholders also turns out to be exaggerated. Recent scholarship has demonstrated that free bank failures were not as common and resulting losses to noteholders were not as severe as earlier historians had claimed.
The American Currency Exhibit at the Federal Reserve Bank of San Francisco states a few interesting factoids about the free banking period, mostly about the negative but funny aspects that are unimaginable today. However, Greenspan says:
During the Civil War, today's bank structure was created by the Congress. It seems clear that a major, if not the major, motivation of the National Bank Act of 1863 was to assist in the financing of the Civil War. But the provisions of the act that incorporated key elements of free banking provide compelling evidence that contemporary observers did not regard free banking as a failure. These provisions included free entry and collateralized bank notes.