Short answers, pulled from the story.
The Theosophical Society was established on the 7th of September 1875 by Helena Blavatsky, Henry Steel Olcott, and William Quan Judge. They met at a gathering called the Miracle Club in New York City to form this organization.
The headquarters of the Theosophical Society moved to Adyar in Tamil Nadu, India during the early 1880s. This location became the center for the main organization after its founding in the United States.
Helena Blavatsky taught that spiritual adepts known as the Masters exist around the world but primarily reside in Tibet. She claimed these figures possessed supernatural powers including clairvoyance and the ability to project their soul instantly to any location.
After Blavatsky died in 1891, tensions erupted within the society over leadership succession leading to a split. In April 1895 the American section voted to secede from the main organization while Annie Besant led the Adyar-based Society.
Many prominent scientists and artists including Thomas Edison, Alfred Russel Wallace, Hilma af Klint, Wassily Kandinsky, and Piet Mondrian belonged to or were influenced by the Theosophical Society. Their work involved presenting spiritual concepts visually or creating music influenced by Theosophical symbolism.