Nicolas de Harlay, seigneur de Sancy Maximilien de Béthune, duc de Sully. Meanwhile he had been a second time converted to Catholicism, but his influence at court waned, and he retired from public life in 1605. He survived until 13 October 1629, leaving a "Discours sur l'occurrence des affaires". His son, Achille Harlay de Sancy (1581–1646), was bishop of Saint-Malo. The Sancy diamond's known history began circa 1570 in Constantinople when purchased by de Sancy. Something of a gem connoisseur, de Sancy used his knowledge to prosperous advantage. Henry III of France suffered from premature baldness and tried to conceal this fact by wearing a cap.
Chastreix-Sancy on and between the Puy de Chabane and Mont Redon, on the west side of the Puy de Sancy, which is part of an ancient stratovolcano which has been dormant for 220,000 years. It is within the Parc naturel régional des volcans d'Auvergne and the commune of Chastreix in the Puy-de-Dôme "département" of the Auvergne "région". It is about 40 km south west of the "préfecture" of the Puy-de-Dôme "département" Clermont-Ferrand, also capital of the Auvergne. The resort is sandwiched between the Cirque de la Fontaine Salée to the south-east and the Val d'Enfer, or Valley of Hell in English,