The first country to be called an “empire on which the sun never sets” was not Britain, but Spain.
At its height in the 16th century, Spain’s territory spanned Europe, the Americas, Asia, and Africa. Wherever the sun traveled, there was almost always a piece of land ruled by the Spanish king bathed in its light.
It possessed Europe’s most elite army, occupied the richest regions of the Americas, and a continuous stream of colonial revenue flowed back to Europe.
Logically, with such vast territory and wealth, Spain should have maintained its position as the world’s hegemon for a long time.
However, just a century or two later, Spain gradually lost its advantage. The Netherlands seized its position as a commercial center, Britain replaced its maritime supremacy, and when people later spoke of the “empire on which the sun never sets,” they no longer thought of Spain first, but of Britain.
Of course, there are many reasons for Spain’s decline.
But if we were to look for a single, most crucial, most dramatic, and most easily overlooked turning point, the answer might trace back to a royal succession.
More precisely, a royal marriage.
A Founding Couple Forged the Spanish Empire
In the late 15th century, Queen Isabella I of Castile married King Ferdinand II of Aragon.
Their union laid the foundation for the later formation of a unified Spanish state. They conquered Granada, ending the centuries-long Reconquista on the Iberian Peninsula.
In 1492, they also sponsored the Italian Christopher Columbus’s voyage across the Atlantic, thereby opening the door for Spanish expansion into the Americas.
Thereafter, Spain conquered the Aztec and Inca Empires, controlling vast swathes of land in the Americas. This nation, originally located in the southwestern corner of Europe, rapidly grew into the world’s first global empire.
However, Isabella and Ferdinand did not leave an heir who could smoothly inherit the throne.
The heirs who were originally in line for succession passed away one after another, and the right to the throne ultimately fell to their daughter, Juana.
Juana married Philip of the House of Habsburg.
It was this marriage that changed the destiny of the Spanish Empire.
The Habsburgs: The “Royal Family of Royal Families” in Europe
The House of Habsburg was not an ordinary European royal family.
It was one of the most powerful, longest-ruling, and most influential dynastic families in European history.
This family ruled Austria for a long time and, through marriage and inheritance, brought the Netherlands, Bohemia, Hungary, Spain, and parts of Italy into its family domain.
A saying once circulated in Europe:
Let others wage war; you, happy Austria, marry.
This phrase perfectly described the House of Habsburg.
While other royal houses often had to rely on war to seize territory, the Habsburgs were adept at bringing one kingdom and dominion after another under their family’s rule through marriage.
Juana and Philip’s son, Carlos, later inherited the Spanish throne, becoming Charles I. At the same time, he also inherited the Netherlands and the Habsburg lands in Central Europe, and was elected Holy Roman Emperor Charles V.
Thus, the King of Spain was no longer just the King of Spain.
He was also the ruler of numerous territories across Europe and the supreme representative of the Habsburg family’s interests.
Spain transformed from a rapidly rising Iberian nation into the most important and wealthiest part of the vast Habsburg dynastic system.
Spain’s Revenue Began to Serve the Entire Dynasty
A king who ruled only Spain would naturally prioritize Spain’s security, construction, and long-term development.
However, a monarch who simultaneously ruled the Netherlands, Italy, Central Europe, and Spain would no longer consider only Spain.
He had to defend the Habsburg family’s territories and status throughout Europe.
France was his enemy, the Ottoman Empire was his enemy, the Protestant princes of Germany were his enemies, and the rebels in the Netherlands were also his enemies.
France, Italy, Germany, the Netherlands, and the Mediterranean—armies and money were needed everywhere.
Some of these wars were related to Spain’s security, while others served more to protect the Habsburg family’s territories, thrones, and European hegemony.
But no matter where the wars took place, Spain and its overseas colonies were one of the most important sources of funding.
The immense profits generated by the American colonies were not prioritized for reinvestment in Spain—to improve domestic agriculture, develop manufacturing, build ports, cultivate talent, or improve the lives of ordinary people.
Vast amounts of wealth were poured into the Habsburg family’s wars across Europe, used to maintain a dynastic system that spanned multiple countries.
Spain bore the primary costs of imperial expansion, but the empire’s profits were not sufficiently reinvested within Spanish society.
This is the core of the problem.
The Habsburg Royalty Was Loyal to the Family First, Not the Nation in the Modern Sense
People today easily understand history through the lens of the modern nation-state.
We assume that a country’s king should, of course, put the interests of his own country first.
But in 16th-century Europe, dynastic interests often outweighed national interests.
A king was first a member of a particular family, and only then the ruler of a certain land.
In the eyes of the Habsburg monarchs, the territories of Spain, the Netherlands, Italy, and Central Europe were all different inheritances belonging to the family.
When Spanish wealth was used to defend the Netherlands or fight for Italy, they didn’t necessarily see it as “spending their country’s money on a foreign country,” because in the eyes of the dynasty, these places all belonged to the same family system.
But for the native inhabitants of Spain, the situation was completely different.
The colonies were conquered and managed by the Spanish, taxes were mainly borne by Spanish society, and a large number of soldiers also came from Spain.
Yet these resources were continuously poured into wars far from the Spanish homeland.
The House of Habsburg gained the capital to maintain its European hegemony, but mainland Spain shouldered an increasingly heavy financial and social burden.
On the surface, Spain possessed an immensely vast empire, but in reality, it gradually became the financial and military pillar of this transnational dynasty.
The Empire Grew Larger, but Spain Itself Did Not Grow Stronger in Sync
Spain reaped enormous colonial profits from the Americas.
But a country’s true strength is not just about how much wealth the king and the treasury control; it’s also about whether that wealth can remain within the country and be converted into domestic industry, technology, education, commerce, and social development.
The most serious problem of the Spanish Empire was precisely this gradual separation of imperial wealth from the nation’s own development.
Colonial revenues seemed to belong to Spain, but in reality, they were constantly mobilized by the Habsburg monarchy to solve the family’s military and political problems throughout Europe.
Spain received the name and glory of an empire but bore its heaviest costs.
The state levied taxes for long periods, young men were constantly sent to fight across Europe, and colonial profits were preemptively invested in the next war.
Spain increasingly resembled a base providing troops and funds for the House of Habsburg, rather than the center to which the empire’s profits ultimately returned.
The empire kept expanding on the map, but Spain itself failed to simultaneously build the economic and social foundations necessary to sustain its hegemony in the long run.
This also explains why Spain could reach its zenith in a short period but was unable to maintain this advantage for long.
Britain Later Imported a German Royal House, So Why Didn’t It Repeat Spain’s Fate?
Some might ask, Britain was also later inherited by a foreign German royal house.
In 1714, George I from Hanover inherited the British throne, establishing the House of Hanover.
Why didn’t Britain, like Spain, allow its national wealth to serve the family interests of a foreign royal house on the European continent?
The reason is simple.
By the time the House of Hanover came to Britain, the country had already established a parliamentary system capable of constraining the king.
The British king could not levy taxes, incur debt, or control the national treasury entirely according to personal and family interests. Major financial and war policies had to receive parliamentary support.
Although the Hanoverian king also possessed German territories, he could not arbitrarily turn Britain into an ATM for the interests of the House of Hanover.
In other words, when the House of Habsburg entered Spain, the royal family dominated the state.
But when the House of Hanover entered Britain, it had to accept the constraints of the British system.
They were both foreign royal houses, but they faced two completely different countries.
Spain’s system could not prevent the monarchy from using the nation’s revenue for the entire House of Habsburg.
Britain’s system, however, could force a foreign king to first rule Britain according to British rules.
A Marriage That Changed the Ownership of Imperial Wealth
Of course, there isn’t just one reason why Spain was replaced by Britain.
But not all historical explanations need to be exhaustive.
What is truly worth remembering is that just as Spain had unified and begun its overseas expansion, an accident of royal succession brought it into the Habsburg family’s system of rule.
From then on, Spain’s colonies, taxes, army, and national power no longer served Spain alone, but also had to serve the Habsburg family’s territories and political goals across Europe.
Spain acquired the world’s first global empire.
But the profits generated by this empire were not sufficiently left for the Spanish homeland and its people.
Britain later also welcomed a foreign royal house, but it had already established a system to limit royal power.
Therefore, Britain could use its imperial profits to develop Britain, while Spain’s profits were long used to maintain a dynasty spanning Europe.
This may be the key difference in why the two “empires on which the sun never sets” ultimately met different fates:
The Spanish state served the royal family, while the British royal family was gradually forced to serve the state.
The marriage of Isabella and Ferdinand created Spain.
But their daughter’s marriage brought Spain into the House of Habsburg’s struggle for European hegemony.
One royal marriage brought Spain to the pinnacle of the world.
Another royal marriage also changed the ultimate destiny of this empire.