The Duchess of Rio Tinto by Martin Murphy

The Duchess of Rio Tinto: The Story of Mary Herbert and Joseph Gage by Martin Murphy ©amazon
The Duchess of Rio Tinto: The Story of Mary Herbert and Joseph Gage by Martin Murphy

The Duchess of Rio Tinto: The Story of Mary Herbert and Joseph Gage

Author:  Martin Murphy
ISBN:  9780571247905
Publisher:  Faber and Faber
Price: 135 pp. £12.99.dd

Lady Mary Herbert, daughter of the second Marquess of Powis, and her lifelong admirer Joseph Gage, were legendary 18th-century adventurers who ran the Guadalcanal and Rio Tinto mine from the late 1720s to 1740s.

In 1719-1720, this unconventional couple made and lost enormous fortunes speculating in shares of the Mississippi Company. Launched by Scottish economist John Law, who was Controller General of Finances in France, the company was a bold attempt to resolve the country's debt problems caused by Louis XIV's long and costly wars. The Miississippi Company had a monopoly on trade and mineral wealth in the French colonies of North America and the East Indies, encouraging European settlers to colonise the Mississippi Valley in Louisiana. Law exaggurated the area's wealth, which led to wild speculation in shares.

In his Epistle to Bathurst, Alexander Pope satirised Mary and Joseph as representative of those who had betrayed their class by adopting the morals of the marketplace. Mary's reputation for financial wizardry made her a target for fortune-hunting suitors of the highest rank, such as the Chevalier de Vendôme and the Duc d'Albret.

When the Mississippi Company bubble burst, Mary tried to recoup her losses with mining operations in southern Spain, starting in the late 1720s. She obtained a contract to work the Guadalcanal (Sierra Norte de Sevilla) mine thanks to her family's successful lead-mining operations in Montgomeryshire. Following sucessful draining of the Guadalcanal mine, and a long lawsuit she was awarded 30 year consession to Rio Tinto mine as well. All the profits made from the Welsh mines went towards paying off her debts, leaving her with insufficient capital to fund her Spanish projects.

The speculations of Mary and Joseph in Paris had been funded by loans from the Irish-French merchant and banker Richard Cantillon, whom they later sued on charges of fraud and usury. Their lawsuits drove Cantillon from Paris to London, where he died 1734 in mysterious circumstances known as 'the case of the headless banker".

Like Mary, Joseph Gage was a Catholic and a Jacobite, who first made his name in Paris as a professional gambler and a protégé of the Dowager Duchess of Orléans. After the collapse of Law's venture in 1720, he went into hiding in the Parisian underworld, before joining Mary Herbert in Spain as the prospector and manager of her mines until the 1740s. She needed him as a factotum, but eluded his attempts to make her his wife. She was still unmarried when she died in 1775 at the age of 89. Her last years were spent at an apartment in the Temple granted her by the Prince de Conti.

Based largely on the Powis Castle archive in the National Library of Wales, The Duchess of Rio Tinto tells a compelling story which is also a colourful portrait of its age.

Reviews of The Duchess of Rio Tinto

'I think you have done marvels ... The book was a pleasure to read throughout' - Ian Robertson, author of The Blue Guide to Spain.

'I have to say that I found your research fascinating. For the first time the life and times of one of the most enigmatic members of the Gage family have been sorted and set straight. You have been absolutely diligent in your research. This is an amazing story, set against an intriguing time in history'. - Deborah Gage, descendant of Jospeh Gage.

'Murphy's researches reveal an incredible story ... No-one could wear great learning more lightly'. -  Oxford Times.

'Vivid, descriptive and enthralling ... Will appeal to a wide range of readers.'- Welsh Historical Review.

'A fascinating book that suggests many tantalising lines of thought about the workings of gender and social rank in the Jacobite diaspora' - Journal of the Royal Stuart Society.


Martin Murphy is a Fellow of the Royal Historical Society and a former Research Associate of the Oxford Dictionary of National Biography.


Copies may be obtained through bookshops, or directly from the author, Martin Murphy at 12 Phelps Place, Oxford OX4 1AZ (cheques payable to G.M.Murphy).

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