Okay, so I think Nicolai's source is Friedrich Leopold von Hertefeld, son of Ludwig Casimir von Hertefeld. Who doesn't have wiki entry of his own, but Fontane is helpful in this case, see these excerpts, which cover Ludwig Casimir. Most important bit translated:
Ludwig Casimir was born in 1709 and joined the Gensdarmes regiment in 1728, so he was a regimental comrade of Hans Hermann von Katte for two more years. In 1743, after having participated in the First Silesian War, he resigned from the service. Again seven years later, in 1750, he became chamberlain to the widowed Queen Sophie Dorothee, mother of Frederick the Great, and remained in this position until her death in 1757.
Fontane also says he was into books and built a library building on his Liebenberg estate. He went back to Boetzlaer (near Xanten and Kleve) in 1777 and died in 1790.
So I strongly suspect that he got to know Peter while he was chamberlain for SD.
Lehndorff by the way? Not impressed:
April 15th, 1753. I get up at three to go to Potsdam; a journey I would dislike if I wouldn't find my dear Prince Heinrich there. My travelling companion is Herr v. Hertefeld, chamberlain of the queen-mother, a very unpleasant man and a babbler ["Schwätzer"] like a woman.
and:
April 4th, 1756. [...] He is a guy who is judged unfavourably by people. He left service during the war und spent six years living quietly on his estate. Finally the queen-mother chose him for chamberlain on recommendation of Chancellor [Cocceji]'s wife, who is his wife's sister, an excellent, witty, and amiable woman, only her voice has something from a dragoon.
Von Hertefeld's wife = Susanne von Bechefer (see this wiki article about v. Hertefeld's father Samuel, who himself held a couple of positions during FW's time). I think Lehndorff is still talking about Cocceji's wife with his description, it's a bit ambiguous even in German, but he definitely likes v. Hertefeld's wife a lot more than the guy, see also this entry from September the same year: Hertefeld with his special gift to bore his listeners only likes those who have the patience to listen to him. and again in December: the man is as unpleasant as his wife is the opposite. One of their daughters seems to have been lady-in-waiting with EC, Lehndorff mentions her quite a lot. Fontane says that's the only daughter they had, so I'm not sure how and if they are also related to the young lady who was with Amalie and died young of tuberculosis, which apparently inspired Fritz to write a poem to Amalie in 1770. ETA: Oh, I just realized that Fontane said they only had one daughter by the time Luwdig Casimir died, so I guess the woman who died in 1770 might have been his daughter as well.
Lehndorff also lists v. Hertefeld as one of the guys who carried AW's coffin.
Hertefelds
Ludwig Casimir was born in 1709 and joined the Gensdarmes regiment in 1728, so he was a regimental comrade of Hans Hermann von Katte for two more years. In 1743, after having participated in the First Silesian War, he resigned from the service. Again seven years later, in 1750, he became chamberlain to the widowed Queen Sophie Dorothee, mother of Frederick the Great, and remained in this position until her death in 1757.
Fontane also says he was into books and built a library building on his Liebenberg estate. He went back to Boetzlaer (near Xanten and Kleve) in 1777 and died in 1790.
So I strongly suspect that he got to know Peter while he was chamberlain for SD.
Lehndorff by the way? Not impressed:
April 15th, 1753. I get up at three to go to Potsdam; a journey I would dislike if I wouldn't find my dear Prince Heinrich there. My travelling companion is Herr v. Hertefeld, chamberlain of the queen-mother, a very unpleasant man and a babbler ["Schwätzer"] like a woman.
and:
April 4th, 1756. [...] He is a guy who is judged unfavourably by people. He left service during the war und spent six years living quietly on his estate. Finally the queen-mother chose him for chamberlain on recommendation of Chancellor [Cocceji]'s wife, who is his wife's sister, an excellent, witty, and amiable woman, only her voice has something from a dragoon.
Von Hertefeld's wife = Susanne von Bechefer (see this wiki article about v. Hertefeld's father Samuel, who himself held a couple of positions during FW's time).
I think Lehndorff is still talking about Cocceji's wife with his description, it's a bit ambiguous even in German, but he definitely likes v. Hertefeld's wife a lot more than the guy, see also this entry from September the same year: Hertefeld with his special gift to bore his listeners only likes those who have the patience to listen to him. and again in December: the man is as unpleasant as his wife is the opposite. One of their daughters seems to have been lady-in-waiting with EC, Lehndorff mentions her quite a lot.
Fontane says that's the only daughter they had, so I'm not sure how and if they are also related to the young lady who was with Amalie and died young of tuberculosis, which apparently inspired Fritz to write a poem to Amalie in 1770. ETA: Oh, I just realized that Fontane said they only had one daughter by the time Luwdig Casimir died, so I guess the woman who died in 1770 might have been his daughter as well.Lehndorff also lists v. Hertefeld as one of the guys who carried AW's coffin.