page_title: Battle of Herbsthausen
section_title: Background
hierarchical_section_title: Battle of Herbsthausen / Background
caption_attribution_description: Franz Von Mercy
context_page_description: The Battle of Herbsthausen, also known as the Battle of Mergentheim, took place near Bad Mergentheim, in the modern German state of Baden-Württemberg. Fought on 2 May 1645, during the Thirty Years War, it featured a French army led by Turenne, and a Bavarian force under Franz von Mercy.
  In February, 5,000 Bavarian cavalry were detached to support the Imperial army in Bohemia, most of whom were lost in the defeat at Jankau on 6 March. Mercy avoided Turenne until he had assembled enough troops, and surprised him at Herbsthausen on 5 May. The battle was short, as the inexperienced French infantry dissolved, and over 4,500 prisoners were taken.
  In August, Mercy was killed at Second Nördlingen, where both sides suffered casualties of over 4,000 each. Although fighting continued, a military solution was no longer possible, and increased the urgency of negotiations that led to the 1648 Peace of Westphalia.
context_section_description: The Thirty Years War began in 1618 when the Protestant dominated Bohemian Estates offered the Crown of Bohemia to fellow Protestant Frederick of the Palatinate, rather than conservative Catholic Emperor Ferdinand II. Most members of the Holy Roman Empire remained neutral, and the revolt was quickly suppressed. An army of the Catholic League, dominated by Bavarians, then invaded the Palatinate and sent Frederick into exile.  
  His replacement by the Catholic Maximilian of Bavaria changed the nature and extent of the war. It drew in Protestant German states like Saxony and Brandenburg-Prussia, as well as external powers like Denmark-Norway. In 1630, Gustavus Adolphus of Sweden invaded Pomerania, partly to support his Protestant co-religionists, but also to control the Baltic trade, which provided much of Sweden's income. 
  Economic factors meant Swedish intervention continued after Gustavus was killed in 1632, but conflicted with states within the Empire, like Saxony, and regional rivals, such as Denmark. Most of Sweden's German allies made peace in the 1635 Treaty of Prague. The war lost its religious nature, and turned into a contest between the Empire and Sweden, supported by France and George Rákóczi, Prince of Transylvania. 
  Ferdinand III, who succeeded his father in 1637, agreed to peace talks in 1643, but ordered his diplomats to delay, hoping for a military solution. However, in 1644 the Swedes defeated the Danes, who re-entered the war as an Imperial ally, then destroyed an Imperial army in Saxony. Despite victory at Freiburg in August 1644, the Bavarians under Franz von Mercy were unable to prevent the French capturing Philippsburg, and occupying Lorraine. Mercy withdrew into Franconia, and established winter quarters at Heilbronn.  
  In 1645, Swedish commander Lennart Torstensson proposed a three part attack on Vienna, to compel Ferdinand III to agree terms. While the French advanced into Bavaria, Rákóczi would join forces with the Swedes in Bohemia, who would then move against Vienna. Mercy sent 5,000 veteran Bavarian cavalry under Johann von Werth to reinforce the Imperial army in Bohemia, which was heavily defeated at Jankau on 6 March.
  Armies of this period relied on foraging, both for men and the draught animals essential for transport, and cavalry; by 1645, the countryside was devastated by years of constant warfare, and units spent much of their time finding supplies. This limited operations and materially impacted the battle, since Turenne had widely distributed his army in order to support themselves. Of his 9,000 soldiers, 3,000 never made it onto the battlefield, while many others arrived too late to influence the outcome.
caption: Bavarian commander Franz von Mercy; killed at Nordlingen in August 1645
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