After his return to Weimar in 1775, Frederick moved into Tiefurt House. He was introverted, and at this time, he had already alienated from his brother. Later, he found himself unable to build up a relationship with his sister-in-law or with Goethe. He turned to music and fell in love with Caroline von Ilten. However, his relatives and Goethe held that she was lower nobility, and therefore unsuitable for a marriage and he had to end the relationship. Goethe wrote to Charlotte von Stein: ... I am being blamed for Caroline's tears, and I'm guilty. Anna Amalia, Frederick's mother, held that only "beggar princes" would fall in love with ladies below their station. Frederick then went travelling. His brother Charles Augustus wrote to Knebel that he had received a letter from London, which ... had no contents, except he wishes me a happy birthday.
After mediation by his brother, Frederick joined the army of the Electorate of Saxony. He was promoted to lieutenant general and maintained a regiment in Naumburg. During the War of the First Coalition, he was a major general. His regiment marched to the Rhine with a Prussian army. He was infected with dysentery when his regiment was encamped near Pirmasens and died when they reached Wiebelskirchen (today part of Neunkirchen). He was buried in the St. George church in Eisenach.
He died unmarried.
References
Heinrich Düntzer: Aus Goethe's Freundeskreise: Darstellungen aus dem Leben des Dichters, Brunswick, 1868, p. 467 ff (Online)
Konrad Kratzsch: Klatschnest Weimar, Würzburg, 2002, p. 47 ff (Online)
Henrich Düntzer in: Westermanns Monatshefte, vol. 5, Brunswick 1859, p. 23 ff (Online)
