One marriage in 1272 founded a dynasty that still reigns in Spain
When Robert, youngest son of Saint Louis IX, married the heiress of Bourbon in 1272, his line spent three centuries as minor royals. Then the Valois kings died out, a Protestant from Navarre took the French crown, and Bourbons went on to rule Spain, Naples and Parma; they still sit on thrones in Spain and Luxembourg.
Robert's son Louis was created Duke of Bourbon in 1327, but the senior line ended in 1527 when Constable Charles de Bourbon, who had fought for Emperor Charles V and lived in exile, died during the Sack of Rome. Leadership passed to the Vendome branch. Antoine de Bourbon became King of Navarre by marriage in 1555, and by 1525 every prince of the blood outside the king's immediate family was already a Bourbon. When the last Valois, Henry III, was assassinated in 1589, French succession law handed the crown to Antoine's son.
That son, Henry IV, had a winding path to power. Baptised Catholic and raised Calvinist, he led the Huguenots, survived the St Bartholomew's Day Massacre of 1572 by converting, then renounced the conversion in 1576. Catholic France refused a Protestant king and backed his uncle, a cardinal, instead. Henry won at Ivry in March 1590 but still could not take Paris, so in 1593 he converted once more and was crowned at Chartres in February 1594. His Edict of Nantes in 1598 kept Catholicism official while granting Protestants limited toleration, ending the religious wars. With the Duke of Sully he cut the land tax, built roads and France's first canal, and founded the Gobelins tapestry works before his assassination in 1610.
His descendants held France until the Revolution toppled the monarchy in 1792, returned after Napoleon, and lost power for good in 1830; the Orleans cousins then reigned until 1848. Spain came through inheritance: the childless Charles II left his crown to a grandson of Louis XIV, who became Philip V in 1700, and the Treaty of Utrecht in 1713 kept the French and Spanish crowns permanently apart. Spanish Bourbons have been ousted and restored repeatedly, reigning most recently since 1975.
Other branches ruled Naples, Sicily and Parma, and Luxembourg's grand dukes became Bourbons after Grand Duchess Charlotte married Prince Felix of Bourbon-Parma. Since 1733 the Bourbons have been the only surviving legitimate branch of the Capetian royal house, and every legitimate living member descends in the male line from Henry IV.
Source: House of Bourbon
