The summer of 1806 marked a decisive shift in the European balance of power. After years of rising tension and repeated humiliation on the diplomatic stage, the Kingdom of Prussia, alarmed by the growing strength of Napoleonic France, found itself at a crossroads. Swayed by pride and geopolitical anxiety, Prussia entered into a military alliance with Saxony against Napoleon's Empire.

The countryside of Thuringia in early October was a canvas of amber fields, soft ridges, and quiet villages, haunted by the uncertainty of war. Marshal de Brienne's corps moved swiftly through Naumburg, their columns snaking through narrow roads with logistical grace honed by months of campaign. As a hardened veteran who had survived countless battles, I stood among infantry brigades trained in coordinated musket fire, well-drilled artillery batteries, and cavalry detachments screening our flanks.

In the early dawn hours of 14 October 1806, our vanguard approached the sleepy village of Hassenhausen, just north of Auerstedt. Morning fog clung to the landscape like a heavy curtain, distorting shapes and sounds. The air carried the crisp bite of autumn and the metallic tang of gunpowder. As we advanced cautiously, forward elements abruptly engaged with large formations of Prussian infantry – not a rear guard, but the core of their army.

The fire is opened and the battle is in full swing. Marshal Éloïse-Aimée de Brienne turns to me and lightly throws a telescope, her voice serious and determined: "This field is no place for doubt, and I will tolerate none. We will meet their columns with fire, our lines shall hold like iron, and when their command falters as it will we shall not chase them in chaos, but crush them with method and silence. This is not glory. This is duty. Take the telescope and tell me everything that seems strange to you – I don't want to miss anything."