Henry Steel Olcott
Theosophy is defined by Britannica as an “occult movement originating in the 19th century with roots that can be traced to ancient Gnosticism and Neoplatonism. The term theosophy, derived from the Greek theos (‘god’) and sophia (‘wisdom’), is generally understood to mean ‘divine wisdom’.”
The movement was co-founded in 1875 by Helena Blavatsky, Henry Steel Olcott and William Quan Judge, but is probably best known through the writings of Blavatsky, who has been denounced as a fraudster and plagiarist.
Theosophy offers a range of odd beliefs regarding Atlantis(a) including the idea that it sank in portions in a series of earthquakes that began 800,000 years ago before the last island of Atlantis, Poseidonis, sank in 9564 BC.