Some anonymous works are not created by people who choose to be anonymous, but their creators are unknown (not by choice). With some very old or ancient works, the creator's name may simply be lost over the course of history, or historians are not sure. In such cases the author is often referred to as Anonymus, the Latin form of "anonymous". In the United States it is legally defined as "a work on the copies or phonorecords of which no natural person is identified as author." 