An Overview
The original formal requirements started with the 1790 Copyright Act. The U.S. continued its policy of requiring formalities until it joined the Berne Convention.
One of the formalities that has been required since the 1790 Act has been that a copy be deposited. Today, these deposits are still required, although now punishable by a fine rather than by loss of copyright protection. This deposit requirement has helped make the Library of Congress the largest library in the world.