🎓 When Royal Marriages Keep Power Inside the Family

How the Egyptians and Ottomans bucked diplomatic marriage trends by marrying their sisters and slaves.

Jul 09, 2025

Throughout history, princesses and other high-ranking royal women spent very little time singing to birds and protecting mice. Mostly, they spent their time running complex households and engaging in high-stakes diplomacy.

Despite the popularity of Cinderella, dynastic marriages were generally the norm, and it was very common for royalty to marry either foreigners who matched their status, or locals whose allegiance could help shore up a weak political position.

Early Chinese dynasties’ complex heqin system bred nomadic vigor into the emperor’s line and provided access to strong women capable of standing against the entrenched bureaucratic state. Romans and Europeans used marriage for strategic alliance-building; Senator Cato the Younger denounced Julius Caesar's orchestrated web of alliances because he found it “disgraceful that Roman power should now be based on trading women.” The Maya had complex inter-city diplomatic networks backed by marriage. The Habsburg dynasty’s motto, “Let others wage war; you, happy Austria, marry!” exemplifies this political strategy.

But it’s not the only marriage strategy around.

While most royal marriages throughout history functioned as diplomatic treaties sealed with wedding vows, the Egyptians and Ottomans1 did something different: they kept everything in-house, embracing precisely the opposite marriage strategy for their elites.

These weren’t societies that lacked the opportunity for international marriage alliances. They were powerful empires with plenty of suitors, who made calculated decisions to prioritize internal stability over external diplomacy. They chose royal marriage systems that actively prevented foreign interference.

Egyptian

Ancient Egypt's approach to royal marriage was so unusual that it was a point of contention with their contemporaries. This is made abundantly clear in the Amarna Letters, when the Mittanian ambassadors were first working out an alliance with Amenhotep III. They refused to fully take part in the “Brotherhood of Kings” — a diplomatic network where rulers from Egypt, Mesopotamia, Syria, and Anatolia created international relationships through marriage alliances. He stated outright that “from time immemorial no daughter of the King of Egypt is given to anyone.”

In the time of Amenhotep, though, they did at least participate some. He successfully used this system to marry foreign princesses from Mitanni and Babylon, securing military and trade advantages. Egypt just didn’t “give back” their own women into the network; they kept one foot in and one foot out of the communal genetic pool, as it were.

It wasn’t until the Ptolemies that Egypt consciously abandoned this halvesies approach in favor of systematic endogamy — in-marriage, as opposed to out-marriage. The system created powerful internal political networks while completely shutting out foreign influence. When Egypt did acquire foreign brides (as earlier pharaohs had done), these marriages were transactional; Egypt received princesses in exchange for gold, and the intent was not to create lasting political bonds. The Egyptian approach was fundamentally defensive, meant to prevent foreign interference rather than actively create international partnerships.

As a bit of background for those not aware, the Ptolemies ruled as a Macedonian Greek minority over a much larger Egyptian population. International marriages risked not just political complications but potential assimilation or displacement of the ruling dynasty. Sibling marriage was an ethnic preservation strategy — it allowed them to maintain their Macedonian Greek identity while ruling Egyptian subjects, without having to bend the knee to Macedonia. The system also emulated Egyptian religious traditions (Isis and Osiris as divine siblings), which helped them cultivate an aura of legitimacy among their subjects.

The Ptolemies prioritized keeping power within the dynasty (through sibling marriage), which ironically made their successions far more violent and unstable than dynasties that married externally. Queens like Arsinoe II, Berenice IV, and Cleopatra VII exercised real power, sometimes as co-rulers and sometimes independently — which added a whole extra set of players to the political board.

The Seleucids, Antigonids, and other successor states to Alexander's empire regularly intermarried to create alliances and settle disputes. The Ptolemies had access to these same opportunities but deliberately rejected them. I’m not sure if this was because of something unique to Egyptian culture or geography, but the Egyptian inbreeding project was not notably more successful on a genetic level than the famously dysfunctional Hapsburg kings. It’s hard to be sure, but the consensus seems to be that they probably had Graves’ disease among other problems.

Almost exactly a year ago, in a comment on an article I wrote about the critical role of gossip in developing early human societies,

OogieM

pointed out that despite the bad rep it gets because of various inbred royal dynasties, incestuous “breeding and close mating is how all domestic species became recognizable breeds.” She added that “If you are trying to concentrate and preserve a recessive trait and there is no DNA test for carriers you will, of necessity, be doing LOTS of close breeding. The problem happens if you refuse to cull appropriately from the resulting offspring.”

In ancient Egypt the process of inheritance was pretty similar to what the Europeans had — in the absence of extenuating circumstances, the firstborn son inherits the property of his deceased father and then becomes responsible for taking care of the other family members. Unlike many ancient societies, Ptolemaic women could and did rule. But generally speaking, and despite all the internecine poisoning and dynastic battles, there wasn’t much culling going on, not the way you’d see in a more explicitly meritocratic inheritance system.

Ottoman

The Ottoman Empire was one of the purest meritocracies I’ve come across, with almost all the important bureaucrats being foreign-born or foreign-blooded. Many high-ranking officials, all the way up to the Grand Vizier, were Christian-born boys from the Balkans who were taken through the devshirme (“child tax”) system, converted to Islam, and educated. Talented ones rose through the ranks of the military and bureaucracy before being married to Ottoman princesses. Princesses married high-ranking male slaves, creating internal power networks binding them to the sultanate… which never quite evolved into an aristocratic class because the next generation of bureaucrats was always pulled from the educated slave class. The whole thing was essentially the opposite of sending princesses abroad to solidify international bonds.

The stereotypical Ottoman inheritance system strikes me as pretty unique. The gist of it is that the sultans stopped marrying foreign princesses and switched to short-term relationships with highly trained, foreign-born slave-concubines. Once the concubine gave birth to a son, she was banished from the sultan’s bed and took up the role of advisor to the prince. When the sultan died, the princes fought it out in a remarkably contained small-scale civil war.

Genetically speaking, they were much more diverse than the Egyptians, but in terms of power-brokering, these women — typically captured from cities and villages in the wake of war, then shipped off to slave markets — brought nothing to the table but their bodies and minds.

To be clear, early Ottoman sultans (14th-15th centuries) followed conventional diplomatic marriage patterns, wedding Byzantine, Balkan, and Anatolian princesses to secure tactical alliances during their rapid territorial expansion — although most sultans reproduced only through slave concubines.

By 1504, Ottoman sultans had completely rejected foreign marriages. Marriage alliances were no longer seen as important to their foreign policy once they had consolidated power. Instead, they opted for their revolutionary concubinage system. In her excellent book Empress of the East, Leslie Peirce explains, “The Ottomans didn't believe that sultans should participate in dynastic marriages with royals from other countries; they felt this might divide the loyalties of any offspring, including successors to the throne.”

This divided loyalty was rather the point of most international marriages; the promise of a truly allied leader on a foreign throne was what led fathers to forge alliances with their daughters’ husbands. But the Ottomans had an unusual aversion to these sorts of divided loyalties, not even permitting mothers to divide their loyalties between multiple sons.

This system of one-son-per-concubine broke down under Suleyman and the slave girl he married after his mother’s death in the 16th century, the woman known as Roxelana. But even after Suleyman’s marriage to Roxelena, his successors continued the practice of choosing harem-trained slave girls as consorts and the mothers of their children.

But, as with Egyptian sibling marriage, the concubinage system that served instead of diplomatic marriage was designed with internal stability as its primary goal. Women were selected from a large class of foreign captives based on intelligence and beauty rather than political connections, and “a concubine would not have the political leverage that would be possessed by a princess or a daughter of the local elite.” This wasn't about romance or even necessarily about power over women — it was about power over the empire. The system largely divorced reproduction from international politics, unlike European systems where royal marriages had both reproductive and diplomatic functions.

The Ottomans chose to bring a certain amount of ‘hybrid vigor’ into the royal bloodlines. Though they didn’t allow foreign princesses to divide the loyalties of their royal sons, royal mothers were able to offer insight into foreign culture — which was valuable in its own way.

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