Why did Johann Wolfgang von Goethe accompany Duke Charles Augustus on military campaigns against France?

Johann Wolfgang von Goethe’s decision to accompany Duke Charles Augustus on military campaigns against France in 1792 and 1793 was primarily motivated by his personal loyalty to the duke.1

During this period, Goethe’s social circle had narrowed, and outside of his household, the duke was his only close friend. This deep personal bond, combined with his political philosophy—often described as "enlightened feudalism"—led him to oppose the French Revolution from its inception. While he held a nuanced view of the political landscape, he believed in the necessity of established authority and felt a sense of personal obligation to the ruler he served.1

These campaigns, which included the retreat from Valmy and the siege of Mainz, served as Goethe's first direct experience with war, an experience he famously found to be a nightmare. As a reward for his loyal support during these difficult times, Charles Augustus later presented him with the freehold of his home on the Frauenplan in Weimar.1