Experience, however, shows that neither a state nor a bank ever have [sic] had the unrestricted power of issuing paper money without abusing that power; in all states, therefore, the issue of paper money ought to be under some check and control; and none seems so proper for that purpose as that of subjecting the issuers of paper money to the obligation of paying their notes either in gold coin or bullion.

The Works of David Ricardo. With a Notice of the Life and Writings of the Author: by J. R. McCulloch (ed. 1846)