Kidnapping a King’s Son, "Kidnapping" Tyrion: The Armagnac-Burgundian War continued
One key episode that led to war between the Armagnac/Orleans and Burgundian parties was the kidnapping of the king's heir, which caused Burgundy and Orleans' relationship to disintegrate. Curiously, one of the key episodes that derailed the Stark-Lannister relationship was Catelyn Stark's "arrest"