Gaston of France, (25 April 1608 – 2 February 1660), also known as Gaston d'Orléans, was the third son of the king of France Henry IV and of his wife Marie de' Medici. He was the Duke of Orléans. As a son of the king, he was a Fils de France. As the eldest surviving brother of King Louis XIII, he was known at court by the traditional honorific of Monsieur.
At the time of the Ring of Fire, Gaston Jean-Baptiste, duc d'Orleans was the heir presumptive to the throne of France, as his brother Louis XIII had no children. He and his entourage of courtiers hated and despised Cardinal Richelieu for his growing power and influence over the French court. The Cardinal in turn realized that once Gaston became king, he would order Richelieu's execution. Gaston was hesitant to act, however; the arrival of Grantville prompted Louis to give Richelieu carte blanche on nearly everything. The Cardinal took this opportunity to crush his enemies, save for the far too-powerful Gaston. Gaston in turn cultivated allies.
By the time of the League of Ostend's crushing defeat at the Battle of Ahrensbök in 1634, nearly every French political figure supported Gaston and opposed Richelieu, whom he blamed for France's embarrassing losses, thus opening the door to a possible civil war.