Zos Kia Cultus is a term coined by Kenneth Grant, with different meanings for different people. One interpretation is that it is a form, style, or school of magick inspired by Spare. It focuses on one's individual universe and the influence of the magician's will on it. While the Zos Kia Cultus has very few adherents today, it is widely considered an important influence on the rise of chaos magic. Austin Osman Spare was loved by Aleister Crowley who was loved by Page. ZoSo is a modified version of Zos Kia Cultus. I read somewhere that Astronomy comes into it.