Valentine Shortis, a young Irish immigrant, was convicted of murder in Quebec in 1895. His insanity defence was unsuccessful in spite of psychiatric evidence given by the leading psychiatrists in Canada. Shortis spent the next 42 years in custody. The case provides a good vehicle for exploring a number of aspects of the history of psychiatry, the insanity defence, and the treatment of the criminally insane in Canada. Comparisons are made with the insanity defence and the treatment of the criminally insane today.