Gabriel Bonnot de Mably (Grenoble, 14 March 1709 – 2 April 1785 in Paris), sometimes known as Abbé de Mably, was a French philosopher, historian, and writer, who for a short time served in the diplomatic corps. He was a popular 18th-century writer. Biography Gabriel Bonnot was born at Mably, Loire into a family that belonged to the Noblesse de robe or Nobles of the Robe. This class formed the Second Estate whose rank derived from holding judicial or administrative posts and were often hard-working professionals, unlike the aristocratic Noblesse d'épée or Nobles of the Sword. He and his older brother Jean added "de Mably" to their names; his younger brother Étienne used another family property, at Condillac, Drôme. As 'Condillac', he also became a noted writer and philosopher. Gabriel and his brothers were educated in an institution run by the Society of Jesus or Jesuits; he enrolled in a seminary at Saint-Sulpice. In 1742, he became a confidant of Cardinal Tencin, then Minister of State without Portfolio, for whom he carried out various diplomatic roles during the 1740 to 1748 War of the Austrian Succession. They included negotiating an alliance with Prussia in 1743 and preparing terms for the 1746 Congress of Breda, which sought to agree a separate peace with Britain. However, he fell out with Cardinal Tencin and thereafter focused on scholarly pursuits. Based on the recommendation of Françoise-Louise de Warens, in April 1740, Mably's older brother Jean employed the 28-year-old Jean-Jacques Rousseau as tutor for his two oldest sons. Rousseau produced two short works addressed to Jean de Mably: "Memorandum Presented to Monsieur de Mably on the Education of Monsieur His Son" and the shorter "Plan for the Education of Monsieur de Sainte-Marie". These outline a proposed system of education for Jean de Mably's sons and also present one of his earliest public self-reflections and self-justifications. By summer 1741, Rousseau realized he was ill-suited to the position and the two agreed to end his employment, parting on friendly terms. The historian Leo Damrosch explains that at this time, Abbé de Mably had just published a treatise comparing Roman institutions of government with French ones and celebrating the progress of civilization ... Conversing with Mably, Condillac, [and friends he had met at Lyon's reading club] Parisot, Bordes, and their friends, Rousseau found himself in a stimulating intellectual milieu, and the studies he had put himself through in