Henry I

Henry I came to the French throne in 1031 amid a family war. A son of Robert II and Constance of Arles, he had been crowned co-king in 1027, yet on his father's death his mother backed his younger brother Robert's claim. Henry prevailed with outside support, but the price of peace was high: he ceded the Duchy of Burgundy to Robert in 1032, establishing the cadet Capetian dukes of Burgundy and removing a substantial territory from direct royal control.

Much of the reign was consumed by the politics of Normandy. Henry initially acted as protector of the young Duke William, the future conqueror of England, supporting him against rebellious Norman barons at the battle of Val-ès-Dunes in 1047. As William's power grew, however, the king reversed course and joined coalitions against him. The resulting campaigns ended badly for the crown, with French forces defeated at Mortemer in 1054 and again at Varaville in 1057. These failures confirmed the duke's independence and foreshadowed the long rivalry between the French kings and the rulers of Normandy.

Henry's marriage diplomacy reached unusually far afield. After earlier marriage plans came to nothing, he wed Anne of Kiev in 1051, a daughter of Grand Prince Yaroslav the Wise of the Rurikid dynasty. The match linked the Capetians to the ruling house of Kievan Rus and brought into the French royal family the Greek name Philip, which Anne gave to her eldest son and which became a recurring royal name thereafter.

Within the kingdom, Henry's effective authority remained confined largely to the royal domain around Paris and Orléans, and his reign is often viewed as a low point of early Capetian power. He nonetheless maintained the dynasty's hold on the crown, having his son Philip crowned co-king in 1059. When Henry died in 1060, the boy succeeded smoothly under the guardianship of Count Baldwin V of Flanders, the king's brother-in-law through his sister Adela, demonstrating that the principle of Capetian succession now stood firmly established.