Hirsig and her older sister Alma were drawn to the study of the occult, and this interest led them in the spring of 1918 to pay a visit to Aleister Crowley, who was living at the time in the Manhattan neighborhood of Greenwich Village.
In 1919, after seeking out Aleister Crowley due to her interest in the occult, she was consecrated as his Babalon or, "Scarlet Woman", taking the name Alostrael, "the womb (or grail) of God."
Of her time there, Frater Hippokleides (2003) writes: At the Abbey, Hirsig was instrumental in guiding Crowley, the Prophet of the New Aeon, to a deeper understanding of the Law of Thelema.
[citation needed] After Raoul Loveday died from drinking contaminated water at Cefalù, Mary Butts reported in one of her journals about Hirsig of an unsuccessful attempt to induce a he-goat to copulate with her at the Abbey of Thelema, emulating an ancient pagan ritual (an account corroborated by Crowley himself in an unpublished passage in one of his diaries).
Hirsig's role as Crowley's initiatrix reached a pinnacle in the spring of 1921 when she presided over his attainment of the grade of Ipsissimus, the only witness to the event.
By June 1924, while Hirsig—the Scarlet Woman—stayed loyal to Crowley during money troubles and painful surgeries for his asthma symptoms, the two of them found their relationship was suffering.
Her diary from this period reveals her continuing devotion to the Great Work, her renewal of her magical oaths, her ongoing invocations of Ra Hoor Khuit, and her consecration of herself as the bride of Chaos.
In 1925, when Crowley asked her to serve again for a period as his scribe and secretary, she readily accepted; she was ready to give her assistance when it was necessary to the furtherance of his magical work and to the promulgation of the Law of Thelema.
[citation needed] On March 13, 1926 her sister Marian Dockerill (born Anna Maria Hirsig), published her exposé on Aleister Crowley, "Oom the Omnipotent" and others in a series of articles which began running on this date in the New York Journal, titled "My Life in a Love Cult, A Warning to All Young Girls".