On April 4th, 1800, Philip Henry Stanhope, then Lord Mahon, wrote from Chevening to his half-sister Lady Hester Stanhope. Then aged just 19, he was worried that his father Charles, Lord Stanhope would soon learn that he was going to “throw myself on the protection of Mr P[itt].”  This was significant, because for many years the 3rd Lord Stanhope and Mr. Pitt had been estranged. They had fallen out over the French Revolution, and their widely divergent political views. The last thing Lord Stanhope wanted was his eldest son to ally himself with Pitt. Growing up, Philip Henry Stanhope was educated at home - at Chevening Estate near Sevenoaks, Kent - instead of being sent abroad or to Europe as was the case during his father's education.
Lord Stanhope was a highly intelligent yet eccentric man, and his three daughters from his first marriage had hitherto flown the nest in order to escape him. His eldest son Mahon was also aligning himself with Pitt. Mahon went as far as calling Pitt his 'Protector.' In the spring of 1800, Mahon wrote to his sister Lady Hester that he was unable “to describe how kind & how generous it is in the “Irresistible Torrent of Eloquence” [Mr Pitt] to take so great an interest in my Welfare and Happiness. I hope by my Conduct & Principles to evince myself worthy of such a Protector; for, as long as Life remains, as long as I continue to exist, as long as one drop of blood flows in my veins & animates my right arm, so long will I continue in steady & determined opposition to Jacobin Principles, Principles which were the origin of this most just & necessary War, Principles which have plunged France into that State of Anarchy & Confusion which have precipitated it into scenes of Rapine & of Violence of Disorder & of Bloodshed, unprecedented & unparalleled in the History of the World, Principles finally of which no words are strong & energetic enough to express my Detestation & Abhorrence.” 
Lord Mahon appealed to his sister for help, describing his situation at Chevening as 'bondage,' and desiring to be freed from his father's house. Yet Mahon was fearful that his father would soon suspect something and have his movements closely watched. He was determined to do every thing that the Irresistible Torrent of Eloquence [Pitt] judged proper, and above all, he wanted out of what he referred to as 'Papa’s Power' .
Needless to say, Lady Hester Stanhope was deeply concerned about her brother. She wrote to her uncle, Mr. Pitt, from Burton Pynsent on April 10, 1800. She was then staying with her maternal grandmother, the Dowager Countess of Chatham, in Somersetshire. In the letter, Lady Hester expressed her anxiety over Mahon's situation, and enclosed a letter from him to Pitt.  She also lovingly described her grandmother, writing "GMama is so unlike all old people I have ever seen, for she enters into every thing with more more quickness than half the world not a quarter her age. She is all goodness to me & I am extremely comfortable here.”  She hoped that Pitt could help Mahon to be freed from his father's estate.
As a result, Pitt did intervene, and Mahon left Chevening. The consequence of this was that Mahon was permanently estranged from his father, the 3rd Earl Stanhope. When Mahon later married Lord Carrington's [Robert Smith] daughter, knowing that Pitt would be present, Stanhope did not attend the wedding. The two men later got into legal battles which I intend to explore in more detail in a later post.
Sadly, all of the 3rd Lord Stanhope's children fell out with their father. It was always permanent. Interestingly, they all sided with Mr. Pitt, viewing him as their 'Protector' when their biological father did not provide for them.
As a postscript, about a month after Pitt's death, on February 26, 1806, Mahon wrote to Pitt's private secretary, W.D. Adams, to enquire whether Pitt's court swords were preserved.  He asked Adams where they were, and that his younger brother Charles Stanhope told him that George Rose meant to preserve the swords for the boys. Mahon was apparently to have Pitt's Court Sword. I wonder whatever happened to the sword, and whether it remains at Chevening to this day?
1. Lord Mahon to his half-sister, Lady Hester Stanhope. April 4, 1800. Dacres Adams MSS: BL Add Ms 89036/2/4: Letters between members of the Stanhope family, f. 92.
4. Lady Hester Stanhope to Mr. Pitt. April 10, 1800. Dacres Adams MSS: BL Add Ms 89036/2/4, f. 93.
6. Lord Mahon to W.D. Adams. February 26, 1806. Dacres Adams MSS: BL Add Ms 89036/2/4, f. 100.