Aleister Crowley served as the Outer Head of the Order from 1922 until his death in December of 1947. Crowley's first act as O.H.O. was to reconfirm the charters of Jones and Tranker as Grand Masters for North America and Germany, respectively. Tranker, on Jones's recommendation, invited Crowley to formally assume leadership of O.T.O. as well as of the various organizations included in the Pansophical movement, at a conference to be held at Hohenleuben, near Weida, in the summer of 1925. The other attendees of the conference were: Heinrich and Helene Tranker; Karl Germer (Saturnus, Jan. 22, 1885 - Oct. 25, 1962), at the time Tranker's secretary and publisher); Albin Grau; Eugen Grosche; Martha Kunzel; Henri Birven; a gentleman named Hopfer; Crowley; Crowley's associates Dorothy Olsen, Leah Hirsig, Norman Mudd; and others.
The results of the conference were mixed. The attendees were divided over Crowley's teachings and The Book of the Law, of which they had previously been largely unaware (it had only recently been translated into German). There were personality conflicts as well. Fraulein Kunzel and Herr Germer went with Crowley. Herrn Tranker, Grau, Hopfer and Birven decided to keep the Pansophical Lodge independent from the Master Therion. Herr Grosche originally sided with Crowley, but he and Germer quarreled, and Grosche decided to remain independent. After the closure of the Pansophical Lodge in 1926, Grosche regrouped a number of the ex-Pansophists to found the Fraternitas Saturni. Fraternitas Saturni recognized Crowley's status as a prophet, and accepted the Law of Thelema in a modified form; but Grosche insisted on keeping it independent from O.T.O. and under his own, rather than Crowley's, authority. Fraternitas Saturni continues to the present day in Germany, Canada and elsewhere, and does not represent itself as being O.T.O.
Tranker apparently attempted to lay claim to the title of O.H.O. of O.T.O. for himself in 1925, but it appears that he was not widely recognized as such and that he ceased his efforts in this direction by 1930, when he and H. Spencer Lewis began to work together directly (but unsuccessfully) to establish a German branch of A.M.O.R.C.
Recommended reading (pdf e-books):
Howard Phillips Lovecraft - The Silver KeyJohn Yarker - The Anglo Saxon Chronicle
Thomas Voxfire - What Was Aleister Crowley
