indicates that the term Gugler is derived from the appearance of the knights dressed for winter, wearing pointed helmets and cowl-like hoods, Gugle being a Swiss German term for cowl or point.
Background
During lulls in the Hundred Years War unemployed knights and soldiers of free companies often rampaged and plundered the French countryside until they were again engaged and paid by French or English overlords to do their bidding. De Coucy gathered a mercenary army of such knights to enforce his inheritance rights versus his Habsburg relatives. The French kingCharles V encouraged and financed de Coucy as he hoped to move these free companies off French lands. There is disagreement about the size of the army De Coucy put together, Tuchman estimates them to be a force of about 10,000 men, a contemporary Alsacian document names 16,000, and other writings place the numbers much higher. As the army was plundering in groups it may not have presented a unified entity. De Coucy's plan was to gain the Sundgau, Breisgau and the county of Ferrette. According to a treaty they had belonged to his Habsburg mother Catherine of Bohemia but were retained by her former brothers-in-law, Albrecht III, Duke of Austria and Leopold III, Duke of Austria.
Course
The mercenary forces assembled in the Alsace and plundered the Sundgau in October and November 1375. Forty villages were wrecked and people were killed or raped. Leopold was unable to defend the Alsace and retreated to Breisach on the Rhine. After Enguerrand's arrival in November some dissension arose about the next course of action. The Alsace had been plundered, winter was approaching, and the knights were unwilling to cross the Rhine. Coucy then led the army south. In December 1375 the Gugler army crossed the Jura mountains, entered the Aare valley and proceeded in three units. Enguerrand de Coucy led the main army that headquartered at the abbey of St. Urban, Jean de Vienne led the second unit and was stationed at the abbey of Gottstatt, and Owain Lawgoch, the leader of the third unit, stayed at the abbey of Fraubrunnen. Some local nobles left their castles and fled to join Leopold, leaving the countryside open to the Guglers. Others resisted, among them Rudolph IV of Nidau, who was killed as the last of the Nidau counts. Resistance was also given by Petermann I von Grünenberg whose attempt to displace the Guglers from St. Urban was thwarted. The pillage by the roaming Guglers affected the western part of the Aargau, where the towns of Fridau and Altreu were completely destroyed. However the populace of the area organized to strike back and, although outnumbered, were able inflict significant damage at Buttisholz on December 19, where 300 knights were killed. The Bernese subsequently formed a citizen army, killed another 300 Guglers with apparently only minor losses at Ins on Christmas night, and led a decisive attack on the Guglers at the abbey of Fraubrunnen on December 27. Owain barely escaped, but another 800 knights were slain. These setbacks, the cold weather, and the obvious resolve of the Swiss populace, led to the retreat of the Guglers; their main army and Enguerrand were not even involved in any pitched battle along the line of retreat.
Aftermath
In January 1376 the Guglers dissolved and returned to plunder the French countryside. Enguerrand compromised with Albrecht III in 1387 and received domain over Büren and part of the town of Nidau which he lost after only one year to the citizen army of Bern and Solothurn. The successful defense of their lands against foreign invaders helped the local people in strengthening their budding independence. They confirmed, after their previous successes at the battles of Morgarten and Laupen, that well organized armies of common men could defeat knightly armour, a feat they would repeat a decade later at Sempach on their route to Swiss independence. The engagements of the Gugler War showed that the epoch of the medieval knight was coming to a close. When questioned by the chronicler Froissart many years later, Enguerrand de Coucy flatly denied he had been in Switzerland at all.
