The Wizard of Oz author, Frank L. Baum and his wife were followers of Theosophy, founded by the occultists, Madame
Blavatsky
Search for the following terms and you will find plenty to read about him. The first page or so of the results praise his practice in the occult. Later, you will find more details exposing his occultic beliefs and the corresponding symbology found in Oz.
Oz Baum Theosophy Blavatsky
By all accounts available, Blavatsky was a Ukrainian Dgoo, Ashkenazi.