It's not my intention to boast, but to revive a history that is ignored.
Shioda Gozo Kancho learned aikido (referred to as "aikibudo" during his earlier years of training) during the pre-war era before WWII. However, Morihei's deep involvment in the esoteric Omoto-kyo of religion and his varied experience later seriously altered the art into something more philosophical minded (and less practical minded) - an approach the Yoshinkan branch did not subscribe to.
No no no, O'Sensei started with the Omoto Kyo in the 1910's well before Mochizuki or Shioda. It was just as important to him then as it was at the end of his life. If any thing actually changed him, it was the war man!