Dr Baker was able to relieve the suffering caused by the Devonshire colic by recommending abstention from the local tipple. Less fortunate are those suffering from an inherited form of porphyria who are prone to periodic attacks of the illness. Even today there is no known cure.
Porphyria was not classified as a distinct medical disorder until the early 20th century, but Dr Baker was soon to find himself in charge of history's most famous porphyria patient. In recognition of his talents, he was knighted and appointed head of George III's medical staff. In this position, he was faced with the familiar symptoms of acute abdominal pain and mental confusion in the sovereign himself. One can only assume that it was the King's additional symptoms - racing pulse, insomnia, general malaise and discoloured excrement - which obscured the similarity between his ailment and the 1759 Devonshire epidemic; Baker recorded that he had never seen anything like the King's symptoms before.
It was not until the 1960s that the hypothesis was advanced that George III, instead of suffering from some indeterminate "madness", was actually porphyric. In controversial articles published in the British Medical Journal, Ida Macalpine and Richard Hunter advanced this view, which was to come to the attention of millions when Alan Bennett made it the subject of his celebrated play and film. Even Bennett was uncertain whether the porphyria theory was proven fact or convenient fiction.
To provide a definitive answer to the riddle of the royal malady, we examined the medical records and correspondence of George III and several of his descendants and also exhumed a granddaughter and a great-granddaughter of Queen Victoria to subject their DNA to genetic tests. We proved, too, that a recently deceased member of the British royal family had suffered from the same disorder. There can now be little doubt that George III did indeed have porphyria, and that the faulty gene was passed on by his granddaughter Queen Victoria to subsequent generations in the British and German royal families.
Does it matter whether George III was disturbed as a result of psychogenic manic depression or because of a fault in his DNA? If we are to understand his character and his impact on decision-making at an important time for the nascent British Empire, the answer must be yes. The implications of our research are far-reaching. Because his attacks of porphyria were caused not by plumbism but by a dominant genetic disorder, the royal mutation may have affected the lives of millions from the early Stuarts down to our own century. Which other monarchs, in Britain and Europe, were affected, and to what degree? By solving one riddle we seem to be confronted with many new questions.
John C. G. Rohl, Martin J. Warren and David Hunt are the authors of 'Purple Secret: genes, "madness" and the royal houses of Europe' (Bantam Press, pounds 16.99)Reuse content