Charles, Duke of Orléans to swear the traditional oath of vengeance for their father's murder. During the early years of his reign as duke, the orphaned Charles was heavily influenced by the guidance of his father-in-law, Bernard VII, Count of Armagnac, for which reason Charles' faction came to be known as the Armagnacs. After war with the Kingdom of England was renewed in 1415, Charles was one of the many French noblemen at the Battle of Agincourt on 25 October 1415. He was discovered unwounded but trapped under a pile of corpses, incapacitated by the weight of his own armour. He was taken prisoner
Duke Charles of Mecklenburg of their cannons and a number of prisoners. On 16 October he fought with distinction at the Battle of Möckern. Leading his brigade in a bayonet charge against the French batteries and columns he succeeded in forcing the section of the line they attacked back but at the cost of his whole brigade almost being taken out with Duke Charles and the other officers all being wounded in the charge. Later that year Duke Charles was appointed to command the "1st of the Line" the oldest regiment of foot in the service. In 1815 Duke Charles was appointed a Lieutenant