The House of Bourbon is a European royal house of French origin, a branch of the House of Capet. Bourbon kings first ruled Navarre and France in the 16th century. By the 18th century, members of the Bourbon dynasty also held thrones in Spain, Naples, Sicily, and Parma. Spain and Luxembourg currently have Bourbon monarchs.
The royal Bourbons originated in 1268, when the heiress of the lordship of Bourbon married a younger son of King Louis IX of France. The house continued for three centuries as a cadet house, while more senior Capetians ruled France, until Henry IV of France became the first Bourbon king of France in 1589. Bourbon monarchs then unified France with the small kingdom of Navarre, which Henry's father had gained by marriage in 1555, and ruled until the 1792 overthrow of the monarchy during the French Revolution. Restored briefly in 1814 and definitively in 1815 after the fall of the First French Empire, the senior line of the Bourbons was finally overthrown in the July Revolution of 1830. A cadet branch, the House of Orléans, then ruled for 18 years (1830–1848), until it too was overthrown.
The Princes of Condé were a cadet branch of the Bourbons descended from an uncle of Henry IV, and the Princes of Conti were a cadet branch of the Condé. Both houses were prominent French nobles until their respective extinctions in 1830 and 1814.
When the Bourbons inherited the strongest claim to the Spanish throne, the claim was passed to a cadet who became Felipe V of Spain. The strict separation of the French and Spanish thrones was formalized in the Treaty of Utrecht in 1714, and similar arrangements later kept the Spanish throne separate from those of the Two Sicilies and Parma. The Spanish Bourbons (in Spanish, the name is spelled Borbón) have been overthrown and restored several times, reigning 1700–1808, 1813–1868, 1875–1931, and from 1975 to the present day. Bourbons ruled in Naples from 1734–1806 and in Sicily from 1734–1816, and in a unified Kingdom of the Two Sicilies from 1816–1860. They also ruled in Parma from 1731–1735, 1748–1802 and 1847–1859.
Grand Duchess Charlotte of Luxembourg married a cadet of the Parmese line and thus her successors, who have ruled Luxembourg since her abdication in 1964, have also been members of the House of Bourbon. Princess Isabel, heiress and regent of the Empire of Brazil, married a cadet of the Orléans line and thus their descendants, known as the Orléans-Braganza, would have ascended to that throne had the empire not ended in 1889. All members of the House of Bourbon and its cadet branches alive today are direct agnatic descendants of Henry IV.