Senarclens de Grancy became the stable master of Louis II, Grand Duke of Hesse, a major general and a knight in the Order of Malta.

It is also alleged that he was the biological father of four of the children of his employer's wife and, therefore, a likely ancestor of Felipe VI of Spain and Charles III of the United Kingdom.

Louis II, Grand Duke of Hesse, bought the Heiligenberg estate near Jugenheim in 1820, where he installed Senarclens de Grancy as his chamberlain later that year.

Louis II's wife, the Grand Duchess Wilhelmine, began living at Heiligenberg during the summers, and wintered at other estates, rarely accompanying her husband from then on.

[citation needed] Grand Duchess Wilhelmine's children born after 1820 were: On 15 November 1836, Senarclens de Grancy married Countess Luise Wilhelmine Camille von Otting und Fünfstetten (born von Schönfeld; 24 May 1810 – 18 May 1876), daughter of Count Friedrich von Otting und Fünfstetten (1767-1834), himself an illegitimate son of the Frederick Michael, Count Palatine of Zweibrücken, and his wife, Wilhelmine, Marquise de Montperny (1788-1874), herself a morganatic granddaughter of Prince William Louis of Baden-Durlach.