It is among the largest and oldest royal houses in Europe and the world, and consists of Hugh Capet, the founder of the dynasty, and his male-line descendants, who ruled in France without interruption from 987 to 1792, and again from 1814 to 1848.
That line was succeeded by cadet branches, the Houses of Valois and then Bourbon, which ruled without interruption until the French Revolution abolished the monarchy in 1792.
The Bourbons were restored in 1814 in the aftermath of Napoleon's defeat, but had to vacate the throne again in 1830 in favor of the last Capetian monarch of France, Louis Philippe I, who belonged to the House of Orléans.
The later Valois, starting with Francis I, ignored religious differences and allied with the Ottoman sultan to counter the growing power of the Holy Roman Empire.
By tradition, younger sons and brothers of the king of France were given appanages for them to maintain their rank and to dissuade them from claiming the French crown itself.
As a result, the Capetians have reigned at different times in the kingdoms of Portugal, Sicily and Naples, Navarre, Hungary and Croatia, Poland, Spain and Sardinia, grand dukedoms of Lithuania and Luxembourg, and in Latin and Brazilian empires.
While the Capetian monarchy began as one of the weakest in Europe, drastically eclipsed by the new Anglo-Norman realm in England (who, as dukes of Normandy, were technically their vassals) and even other great lords of France, the political value of orderly succession in the Middle Ages cannot be overstated.
By comparison, the Crusader Kingdom of Jerusalem was constantly beset with internal succession disputes because each generation only produced female heirs who tended to die young.
Even the English monarchy encountered severe succession crises, such as The Anarchy of the 1120s between Stephen and Matilda, and the murder of Arthur I, Duke of Brittany, the primogeniture heir of Richard I of England.
The latter case would deal a severe blow to the prestige of King John, leading to the eventual destruction of Angevin hegemony in France.
Salic law, re-established during the Hundred Years' War from an ancient Frankish tradition, caused the French monarchy to permit only male (agnatic) descendants of Hugh to succeed to the throne of France.
However, Joan's paternity was suspect due to her mother's adultery in the Tour de Nesle Affair; the French magnates adopted Salic law to avoid the succession of a possible bastard.
The current legitimate, senior family member is Louis-Alphonse de Bourbon, known by his supporters as Duke of Anjou, who also holds the Legitimist (Blancs d'Espagne) claim to the French throne.