Charles the Bald (numbered Charles II of France and the Holy Roman Emperor) (French: Charles le Chauve, German: Karl der Kahle) (13 June 823 – 5 October 877), Holy Roman Emperor (875–877) and king of West Francia (840–877), was the youngest son of Emperor Louis the Pious, by his second wife Judith.

Pippin the Elder (c. 580–640)
Grimoald (616–656)
Childebert the Adopted (d. 662)
Arnulf of Metz (582–640)
Chlodulf of Metz (d. 696 or 697)
Ansegisel (c.602–before 679)
Pippin the Middle (c.635–714)
Grimoald II (d. 714)
Drogo of Champagne (670–708)
Theudoald (d. 714)
Charles Martel (686–741)
Carloman (d. 754)
Pepin the Short (714–768)
Carloman (751–771)
Charlemagne (d. 814)
Louis the Pious (778–840)
Lothair I (795–855) (Middle Francia)
Charles the Bald (823–877) (Western Francia)
Louis the German (804–876) (Eastern Francia) Struggle against his brothers
The first years of Charles's reign, up to the death of Lothair I in 855, were comparatively peaceful. During these years the three brothers continued the system of "confraternal government", meeting repeatedly with one another, at Koblenz (848), at Meerssen (851), and at Attigny (854). In 858, Louis the German, invited by disaffected nobles eager to oust Charles, invaded the West Frankish kingdom. Charles was so unpopular that he was unable to summon an army, and he fled to Burgundy. He was saved only by the support of the bishops, who refused to crown Louis king, and by the fidelity of the Welfs, who were related to his mother, Judith. In 860, he in his turn tried to seize the kingdom of his nephew, Charles of Provence, but was repulsed. On the death of his nephew Lothair II in 869, Charles tried to seize Lothair's dominions, but by the Treaty of Mersen (870) was compelled to share them with Louis the German.
Besides these family disputes, Charles had to struggle against repeated rebellions in Aquitaine and against the Bretons. Led by their chiefs Nomenoë and Erispoë, who defeated the king at Ballon (845) and Juvardeil (851), the Bretons were successful in obtaining a de facto independence. Charles also fought against the Vikings, who devastated the country of the north, the valleys of the Seine and Loire, and even up to the borders of Aquitaine. Several times Charles was forced to purchase their retreat at a heavy price. Charles led various expeditions against the invaders and, by the Edict of Pistres of 864, made the army more mobile by providing for a cavalry element, the predecessor of the French chivalry so famous during the next 600 years. By the same edict, he ordered fortified bridges to be put up at all rivers to block the Viking incursions. Two of these bridges at Paris saved the city during its siege of 885–886.