The marriage of Henry Plantagenet and Eleanor of Aquitaine marked a significant union in the medieval period, solidifying power through strategic alliance. Eleanor was the richest woman in Europe and inherited the duchy of Aquitaine, which encompassed a vast area of southwestern France. Henry, a young nobleman from England with ambitions of throne succession, successfully secured Eleanor's hand in marriage during a time when her former husband, Louis VII of France, divorced her. The union took place in Bordeaux, solidifying a strong political alliance. Their marriage not only provided Henry with the wealth and resources of Aquitaine but also established a connection that would expand his influence over France. The couple would later have eight children, many of whom became prominent figures in European history.

This marriage was instrumental in altering the balance of power in medieval Europe. With Eleanor's lands added to his own, Henry's reach and authority grew, directly affecting the political dynamics of both England and France. The combination of their territories laid the groundwork for the Plantagenet dynasty, which would play a pivotal role in English history. The union also set the stage for enduring conflicts between the French and English crowns, especially during the latter part of the 12th century and beyond.

Henry's ascension to the English throne two years later, following the death of King Stephen, further emphasized the importance of this marriage. It facilitated the consolidation of power that would enable Henry to implement significant reforms throughout his kingdom and expand his influence across the English Channel and into France, which contributed to the foundation of England as a major European power during the medieval era.