the term "third reich" was coined by arthur moeller van den bruck in his 1923 book "das dritte reich". he defined the holy roman empire (962–1806) as the "first reich", and the german empire (1871–1918) as the "second reich", while the "third reich" was an ideal state including all german peoples, including austria. in the modern context the term refers to nazi germany. it was used by the nazis to legitimize their regime as a successor state to the retroactively-renamed first and second reichs.