[1] In the past, historians also argued for Weert in Limburg because they confused him with Jan van der Croon, another imperial general with similar vita.
In this time, he married the Dutch woman Gertrud van Gent, mother of his eldest children Lambertine Irmgard and Johann Anton.
His achievements were even more conspicuous in the great pitched Battle of Nördlingen (1634), after which the emperor made him a Freiherr of the Empire, and the elector of Bavaria gave him the rank of Lieutenant field marshal.
Starting in July 1636, from the country of the lower Meuse, he raided far and wide, and even urged his commander-in-chief, Cardinal-Infante Ferdinand of Austria, to "plant the Double Eagle on the Louvre".
Werth's horsemen appeared at Saint-Denis before a French army of fifty thousand men at Compiègne forced the invaders to retreat.
The memory of this raid lasted long, and the name of "Jean de Wert" figures in folk-songs and serves as a bogey to quieten unruly children.
His first campaign against the French marshal Guebriant was uneventful, but his second (1643) in which Baron Franz von Mercy was his commander-in-chief, was the Battle of Tuttlingen in which Werth was instrumental in a surprise victory.
Werth was disappointed, but remained thoroughly loyal to his soldierly code of honour, and found an outlet for his anger in renewed military activity.
[citation needed] Johann von Werth's life became a popular legend in the Rhineland and Cologne that is frequently reenacted at Karneval time: A poor peasant, Jan, fell in love with Griet but she wanted a wealthier partner and declined his offer of marriage.
After taking the fort at Hermannstein he was leading his triumphant troops into Cologne through St. Severin's Gate, when he saw his former love Griet selling fruit at a market.