The House of Bourbon (Borbón in Spanish) is a European royal house, which originated as a cadet branch of the Capetian dynasty in 1268. The Bourbon house succeeded to the throne of France in the person of Henri IV in 1589. By the 18th century, members of the Bourbon dynasty also held thrones in Spain, Naples and Sicily (later Kingdom of the Two Sicilies), and Parma. In the 21st century, Spain and Luxembourg retain Bourbon monarchs.
In 1713, following the defeat of France and Spain in the War of Spanish Succession, the British-imposed Treaty of Utrecht declared that, while different members of the Bourbon family could rule in France and Spain, the two nations would not unite under a single monarch. This matter became irrelevant with the abolition of the French monarchy in the 19th century.
Bourbon in The Two Georges
By the close of the 20th century, the House of Bourbon retained control over the Franco-Spanish Holy Alliance, one of the world's three superpowers. King François IV, who ruled from Versailles, was the head of this ancient dynasty.
An earlier Bourbon king of France, Louis XVI, had weathered all opposition to his rule in the late 18th century.
In the Atlantis Series, Carlos III of Spain, and Louis' XIV, XV, and XVI of France, are referenced at different parts of Opening Atlantis and/or The United States of Atlantis, set in the 18th century. Their roles differ very little, if at all, from their OTL functions. While there are Atlantis stories set in the 19th century, they don't address the fate of either Bourbon line.
Alfonso XIII of Spain plays a background role in American Empire: The Victorious Opposition and The War That Came Early: West and East. In the latter, his overthrow, and presumably his death, follow the pattern of OTL. In the former, his rule is extended to 1939 (at best estimate), but he is still overthrown.
- The Two Georges, pgs. 444-446, mpb.