The Thirty Years' War reduced the city's population significantly and during the Dutch War in 1677 it was burned to the ground by French troops under the leadership of Marshall de Créquy. Later on, during the eighteenth century, the citizens of Lahr sued the House of Nassau in the "Lahr Law Suits" in 1726 and 1778. The suits were decided in favor of the citizens of Lahr and thwarted Nassau's attempt at absolute rule.