Jean-Florent de Vallière (7 September 1667 – 7 January 1759) was a French artillery officer of the 18th century. He was lieutenant-general of the King's Armies. In 1726, de Vallière became Director-General of the Battalions and Schools of the Artillery.
Through the Royal Ordonnance of 7 October 1732, de Vallière endeavoured to reorganize and standardize the King's artillery. He significantly improved the method used for founding cannons, superseding the technique developed by Jean-Jacques Keller. He thus developed the de Vallière system, which set the standard for French artillery until the advent of the Gribeauval system.
Whereas numerous formats and designs had been in place in the French army, de Vallière standardized the French sizes in artillery pieces, by allowing only for the production of 24 (Canon de 24), 12, 8 and 4 pound guns (the weight is the weight of the cannonballs), mortars of 12 and 8 French inches, and stone-throwing mortars of 15 French inches.
The French pound weighting 1.097 English pounds, the French guns fired slightly heavier balls (13.164 pounds) than their English equivalent 12-pounder. The French inch was 2.707 cm, slightly longer than the English inch of 2.54 cm.
The de Vallière system used core drilling of the bore of cannons founded in one piece of bronze, a method developed at that time by Jean Maritz, which allowed for much higher precision of the bore shape and surface, and therefore higher shooting efficiency.
The de Valliere guns were also highly decorative and contained numerous designs and inscriptions.
The back part occasionally included an inscription showing the weight of the cannonball (for example a "4" for a 4-pounder), followed by a Latin inscription "Nec pluribus impar," meaning that the King is "No unequal match for many," i.e. "None his equal." This was followed by the royal crest of the Bourbon dynasty. The location and date of manufacture were inscribed (in the example "Strasbourg, 1745") at the bottom of the gun, and finally the name and title of the founder (in the example "Fondu par Jean Maritz, Commissaire des Fontes"). The breech was decorated with an animal face showing the rating of the gun (in the example the lion head for a 24-pounder).
The guns had cascabel designs which allowed to easily recognize their rating: a 4-pounder would have a "Face in a sunburst", an 8-pounder a "Monkey head", a 12-pounder a "Rooster head", a 16-pounder a "Medusa head", and a 24-pounder a "Bacchus head" or a "Lion head".