The battle of Auneau (24 November 1587) was the second defeat suffered by a force of Germans that had invaded France in support of the Huguenots and helped convince the survivors to accept an offer of safe conduct out of France (Eighth War of Religion).
The German army was raised by John Casimir, regent of the Palatinate, and largely funded by Elizabeth I of England. Casimir decided not to command in person, and appointed Baron Fabian von Dohna to command the army. This would prove to be a poor decision, as Dohna’s decisions led the army further and further into France, and further and further away from Henry of Navarre, the main Huguenot leader.
The Germans advanced from Alsace into Lorraine, but then turned west to march towards the Loire. This took them on a long march across eastern France, harassed all the time by the Duke of Guise and his brother the Duke of Mayenne, who hovered around their flanks. Eventually the Germans reached Neuvy, on the north bank of the Loire, but they now found a third French army opposing this time, this time the Royal army of the duke of Epernon, who had been joined by Henry III in person. An attempt to cross the Loire further south, at La Charité, failed, and Dohna decided to continue with his march down the north bank of the Loire.
Dohna had one advantage at this point - Guise had no intention of cooperating with Henry III. As the Germans moved north-west to get around the Royal army, Guise advanced on their right, making sure that the Germans were always between him and the King. On 26 October Guise attacked the German camp at Vimory, possibly winning a minor victory, although Dohna’s force continued to push on into France.
As the army moved further into France, the large Swiss contingent began to realise that there was no sensible plan. They entered into negotiations with Henry III, and soon accepted a guarantee of safe conduct if they returned home. This removed more than half of Dohna’s army, leaving him dangerously exposed a few miles east of Chartres. At last Dohna decided to retreat, possibly with the aim of crossing the Upper Loire and joining Henry of Navarre in the south of France. However this plan would also fail.
On 24 November Dohna’s army approached the walled town of Auneau, thirteen miles to the east of Chartres. As he approached the town, Dohna discovered that the local peasants had taken control of the castle, but as they agreed to provide him with the supplies he required he decided to leave it in their hands. Part of his army then took up quarter inside the walled town.
This turned out to be a near-fatal mistake. Henry of Guise had watched Dohna’s march, and had rushed a group of arquebusiers into the castle, where they were now hiding. He then followed with the rest of his army, and prepared to ambush the Germans as they left. Early in the morning of 25 November, just at the moment when Dohna’s men were about to begin their march, Guise attacked from both sides, trapping Dohna’s reiters in the narrow streets of the town. Dohna himself escaped with a handful of men, but most of the troops who had spent the night in the town were either captured or killed.
In the aftermath of this defeat, Dohna managed to rally the rest of his army and continue the march east. He was now being closely watched by Henry III’s army under the duke of Epernon, but the king preferred to find a peaceful solution to the problem. He entered into negotiations with the Germans, and they quickly accepted his offer of safe conduct back to Germany. The remains of Dohna’s army left France via the territory of Savoy and Geneva.
The Duke of Guise was furious that he had been denied a chance to destroy the German army, but Henry III’s approach made much more sense. Henry of Navarre was still at large with his army, and had only recently defeated a Royal army at Courtras (20 October 1587). If the German army had been defeated, Guise and the Catholic League would probably have taken much of the credit, further weakening the Royal position.