A forgotten forty-year conflict shaped the map of the modern Low Countries
The Guelders Wars were not defined by grand field battles, but by relentless raids, ambushes, and hit-and-run tactics. Spanning four decades, this brutal struggle between the House of Burgundy and the Duchy of Guelders ultimately consolidated the Low Countries under the rule of Emperor Charles V.
The origins of the conflict date back to 1471, when Charles the Bold provided a massive loan of 300,000 gold guilders to Arnold, Duke of Guelders. To secure the debt, Charles claimed the title to the Duchy of Guelders. When Arnold died in 1473 without repaying the funds, Charles the Bold assumed control. This sparked a multi-generational military effort by Arnold’s descendants, Adolf and Charles, to reclaim their ancestral territory from Burgundian and later Habsburg authority.
Between 1502 and 1543, the region endured a persistent state of warfare. Rather than engaging in large-scale set-piece battles, the combatants favored asymmetric tactics. Field marshal Maarten van Rossum became notorious for his daring raids, including the 1528 sack of The Hague and a 1542 siege of Antwerp. The human cost was severe, with civilian populations suffering through constant skirmishes and the total destruction of towns like Düren, which marked the final collapse of resistance.
The wars were deeply intertwined with broader European power struggles, including the Italian Wars and the Danish Count's Feud. By the time Charles, Duke of Guelders, died in 1538, he had attempted to bypass Habsburg succession by naming William of Jülich-Cleves-Berg as his heir. However, William’s alliance with France proved insufficient. In 1543, Habsburg forces finally conquered the remaining territories. The subsequent Treaty of Venlo forced the cession of Guelders and Zutphen to Charles V, effectively completing the unification of the Seventeen Provinces.
Source: Guelders Wars
