Attribution (copyright)

In cases when the copyright holder is the author themselves, this behavior is often moralized as a sign of decency and respect to acknowledge the creator by giving them credit for the work.

This said, a work in the public domain, which is any not covered by copyright, has no such attribution requirement in most parts of the world.

This is the distinguishing factor between plagiarism, which is not a crime, but an unethical act, and copyright infringement, which may be a cause of legal action from the author.

In most countries of the world, copyright holder attribution is not required in the original source material, due to the Berne Convention.

In the United States, the preservation of such a notice was formerly an invariable requirement to prevent a work entering the public domain.