Charles VI, King of France, 1368-1422 (Library of Congress Name Authority)—

First referred to as "the Beloved" and later "the Mad," Charles VI ascended to the throne at the age of eleven and increasingly suffered from psychotic episodes that rendered him an ineffectual ruler. Although Charles signed the Treaty of Troyes shortly after the French defeat at the Battle of Agincourt, making his future son-in-law Henry V heir to the French throne, Henry died shortly before Charles, leading to the French re-entering the Hundred Years' War and earning victory for the French House of Valois.

Charles II, King of England, 1630-1685 (Library of Congress Name Authority)—

Exiled to France during the English Civil Wars and Interregnum, Charles II returned to England in 1660 to be crowned king, bringing French court culture as well as artistic and cultural sophistication with him to inaugurate a reign of relative political stability and flourishing arts but characterized by detractors as profligate and immoral.