Atlantis: The Antediluvian World
Its only ancient source is two passages in Plato's Timaeus and Critias, where the speaker Critias insists the tale is true, though most scholars read it as Plato's own philosophical fiction. Donnelly's claim that every ancient civilisation, European ones included, descended from Atlantis was taken up in Blavatsky's The Secret Doctrine and anticipates ancient-astronaut claims.
Plato, Timaeus 20d–25d and Critias; Ignatius Donnelly, Atlantis: The Antediluvian World (1882), Part I, ch. 1; H. P. Blavatsky, The Secret Doctrine (1888), vol. II
An 1882 bestseller by a sitting US Congressman arguing Atlantis was the lost source of all human civilisation.