The Wealth of Nations by Part 1 Chapter 10 Page 120

security which scarce any man who lives by labour can give; and much greater security is frequently demanded.

In order to restore in some measure that free circulation of labour which those different statutes had almost entirely taken away, the invention of certificates was fallen upon. By the 8th and 9th of William III it was enacted that if any person should bring a certificate from the parish where he was last legally settled, subscribed by the churchwardens and overseers of the poor, and allowed by two justices of the peace, that every other parish should be obliged to receive him; that he should not be removable merely upon account of his being likely to become chargeable, but only upon his becoming actually chargeable, and that then the parish which granted the certificate should be obliged to pay the expense both of his maintenance and of his removal.