(21 October 1917 - 28 January 1939) (his death)
By 1916, Yeats was 51 years old and determined to marry and produce an heir. John MacBride had been executed by British forces for his role in the 1916 Easter Rising, and Yeats thought that his widow might remarry. His final proposal to Maud Gonne took place in mid-1916. Gonne's history of revolutionary political activism, as well as a series of personal catastrophes in the previous few years of her life, including chloroform addiction and her troubled marriage to MacBride made her a potentially unsuitable wife and biographer R.F. Foster has observed that Yeats's last offer was motivated more by a sense of duty than by a genuine desire to marry her.
Yeats proposed in an indifferent manner, with conditions attached, and he both expected and hoped she would turn him down. According to Foster "when he duly asked Maud to marry him, and was duly refused, his thoughts shifted with surprising speed to her daughter." Iseult Gonne was Maud's second child with Lucien Millevoye, and at the time was twenty-one years old. She had lived a sad life to this point; conceived as an attempt to reincarnate her short-lived brother, for the first few years of her life she was presented as her mother's adopted niece. When Maud told her that she was going to marry, Iseult cried and told her mother that she hated MacBride. At fifteen, she proposed to Yeats. A few months after the poet's approach to Maud, he proposed to Iseult, but was rejected.
That September, Yeats proposed to 25-year-old Georgie Hyde-Lees (1892–1968), known as George, whom he had met through Olivia Shakespear. Despite warnings from her friends—"George ... you can't. He must be dead"—Hyde-Lees accepted, and the two were married on 20 October. Their marriage was a success, in spite of the age difference, and in spite of Yeats's feelings of remorse and regret during their honeymoon. The couple went on to have two children, Anne and Michael. Although in later years he had romantic relationships with other women and possibly affairs, George herself wrote to her husband "When you are dead, people will talk about your love affairs, but I shall say nothing, for I will remember how proud you were."
During the first years of his marriage, he and George experimented with automatic writing, and George contacted a variety of spirits and guides they called "Instructors". The spirits communicated a complex and esoteric system of characters and history, which the couple developed during experiments with the circumstances of trance and the exposition of phases, cones, and gyres. The spirits notified George that they were ready to communicate by filling the Yeats's house with the scent of mint leaves. Yeats devoted much time to preparing this material for publication as A Vision (1925). In 1924, he wrote to his publisher T. Werner Laurie admitting: "I dare say I delude myself in thinking this book my book of books".