Throughout their lives, Fernando Pessoa and W. B. Yeats displayed a sustained interest in occultism that encompassed different esoteric currents, comprising hermeticism, magic, alchemy, astrology and theosophy. This examination of esoteric influences in their works centres on the Western traditions of the Kabbalah and Rosicrucianism, focusing particularly on Kabbalistic principles largely derived from the teachings and rituals of Rosicrucian hermetic orders. Particular attention is devoted to the metaphor of transmutation of personality and of style that underpinned the articulation of Yeats's theory of the Mask and Pessoa's depersonalisation into heteronyms and elicited parallel strategies of stylistic diversification in their poetry.

Yeats's association with the Rosicrucian occult tradition began with his initiation in 1890 into the Hermetic Order of the Golden Dawn. His long-term involvement with the Order confirms that he ‘found in Rosicrucianism a system of thought which explained his profoundest convictions concerning the relationship of man to the universe’. The Golden Dawn provided Yeats with a ‘framework’ for his metaphysical enquiries, imposed by ‘the discipline of the magical examinations’ that characterised the progression in the Order. As he swiftly progressed to higher grades, he became gradually more involved in creating magical rituals through collaboration with the head and co-founder of the Order, MacGregor Mathers. This process inspired Yeats to create a Celtic mystical Order and, as he states in his autobiography, ‘for ten years to come my most impassioned thought was a vain attempt to find philosophy and to create ritual for that Order’.