Rhodesia-Sierra

Rhodesia-Sierra is a theoretical between the Kingdoms of Rhodesia and Sierra in which it would share the same  and the same ruling. The possibility of a Rhodesia-Sierra first became realized when a relationship between Sierran Queen Angelina II and Rhodesian Crown Prince Henry was made known to the public by the couple in June 2015. Both Sierra and Rhodesia have disputed their claims in pretense to the Crown of Britannia (Britannia abolished the monarchy after the execution of ) by virtue of their houses: the Sierran Columbians from the and the Rhodesian Rhodes from the. Should Angelina II and Henry marry, and King Edward III of Rhodesia were to pass, Angelina would become of Rhodesia while simultaneously reigning as  of Sierra, thus unifying the kingdoms under one family. The legitimate child of the royal couple would then ascend the throne inheriting both crowns, becoming the first monarch of both kingdoms, enjoining the rivaling houses of Columbia and Rhodes under one banner, and the sole claimant to the Britannian crown.

Rhodesia-Sierra, if achieved, would consist of two main regions: the n-based Rhodesia and the n-based Sierra and a total of 29 provinces (7 Rhodesian and 22 Sierran). It would be the 7th largest country in the world by total area with 1,499,446 square miles (3,883,548 km2), putting it ahead of and Argentina but behind  and the 12th largest country in the world by population with 107,801,435 people putting it ahead of Lan Na and  but behind Mexico. It would also feature the world's 3rd largest economy in terms of nominal GDP at $6.516 trillion and the 11th largest military by number of personnel with 1,481,901 active, reserves, and paramilitary troops.

There are several hypothetical forms the union could assume if the crowns were united. Most analysts believe that the union would remain merely a wherein both countries continue to remain their own distinct governments, laws, constitutions, and militaries while still sharing the same head of state or sovereign, the monarch. Another possibility is the integration of both kingdoms into an elevated political union wherein the countries would share the same central government, parliament, military, and foreign policy while still able to exercise a great deal of autonomy. The possibility of a simple political organization encompassing both kingdoms with a non-binding authority system is yet another possibility.

The primary challenges to the union from occurring would be the nations' difference in law and culture. The most notable of these conflicts include the primacy of the Church of Rhodesia in Rhodesia as its with the monarch as its Supreme Governor. In Sierra, the Constitution explicitly forbids the establishment of religion, and would prevent any monarch from assuming the title and power of a religious office or sanctioning a religious institution.