France, ROYAL, Louis XVI, Pattern Écu de Calonne, 1786a, Paris, by J.-P. Droz, in silver, original striking, laureate bust left, rev. three lis surrounded by two Ls in the form of branches of palm and olive, crown above, edge (lis) domine (lis) salvum (lis) fac (lis) regem in six segments, 29.30g/6h (Ci 2202; VG 90). Extremely fine and attractively toned, very rare £2,600-£3,000

The écu de Calonne was so-named after Charles-Alexandre de Calonne (1734-1802), the Controller-General of France appointed by Louis XVI in 1783. His unsuccessful efforts to reform the structure of France's finance and administration precipitated the governmental crisis that led to the French Revolution of 1789. Jean-Pierre Droz (1746-1823), the Swiss engraver first associated with the Monnaie de Paris in 1776, suggested improvements in the manufacture of the French coinage, in the form of a recoinage, in 1783. By 1786 he had produced his pattern écu, a version of which, utilising the same obverse die, was paired with a reverse petitioning Calonne for work (BDM I, 619). Droz devised a ‘plateau’ – a 6-segmented collar which enveloped the blank as it was struck and automatically split open once striking was finished, releasing the finished coin. The principal advantage of this was to allow a raised edge inscription to be applied to a coin within the tight confines of a collar. His efforts to sell the idea to the government failed because of the parlous state of the French economy, but the British entrepreneur Matthew Boulton, witnessing Droz’s equipment at work first-hand in December 1786, seduced the Frenchman to come and work for him at Soho. A lengthy courtship concluded with Droz’s move to England in September 1787