  Leśniewski’s antipathy towards set theory was so vehement and his criticisms so intemperate that it led to a break in relations with his set-theoretically minded mathematical colleagues Sierpiński and Kuratowski; he resigned from the editorial board of Fundamenta Mathematicae, with the result that he was no longer able to publish his own work there. By the end of his life, Leśniewski’s only surviving close friend was the saintly patient and faithful Kotarbiński, who alone of his colleagues visited him in hospital in his last illness. They had been born just days apart in 1886. The cancer that killed Leśniewski was no doubt exacerbated by smoking: cigars and a large pipe. During the operation he was conscious and without anaesthetic because of the dangers and he was allowed to smoke even then to distract himself from the pain. But he did not recover, and died sitting in his favourite armchair, brought specially into the hospital.