Doubts about the sanity of the German Emperor Wilhelm II emerged soon after his accession to the throne in 1888. Chancellor Bismarck, after he was dismissed by the young monarch, was among the first to spread rumours about Wilhelm's alleged mental aberration. The emperor's erratic behaviour was a concern for many of his contemporaries and some drew comparisons to Ludwig II of Bavaria who had been declared insane and deposed in 1886. In 1894, the historian Ludwig Quidde published a study on Roman Caesarean madness that was obviously aimed at Wilhelm II and attracted great public attention. Members of his entourage depicted Wilhelm as a neurasthenic, and after his abdication in 1918 some psychiatrists made an armchair diagnosis of bipolar disorder. The degree to which these diagnoses were accurate may never be known. Wilhelm's adversaries used speculations about his mental state as a political tool to discredit him. This culminated after the First World War when the political dispute about the loss of the war reached the boiling point. Such psychopathological analyses of Wilhelm II demonstrate that, at the beginning of the 20th century, the interpretative authority and expertise of psychiatry was not limited to medicine but reached the political sphere as well. The case also points to the problematic nature of armchair diagnosing and the mingling of psychiatric and political judgement.