After I asked what language the Anglo-French Empire would use, I got a few comments that made me realise that I haven't really thought about how this would arise in the first place. For starters, as pointed out by David Richerby, the British had laws that prevented a monarch from being Catholic. Another point of contention is that the French were an absolute monarchy during the late-17th to mid-18th Century, and the British were a parliamentary monarchy during the same time period. Finally, the Seven Years War and subsequent wars caused both to generally despise each other.

Obviously, the above would have to change, or it would have to happen in spite of the above. So, how would France and Britain merge into a single entity, given the following:

  • It happens in the early to mid-18th Century, i.e. before the American War of Independence, and long before the French Revolution.
  • It starts as a political and possibly military alliance, and by the early-20th Century has been a formal union for at least one generation.
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    $\begingroup$ This question seems too broad to me, but I don't know how it could be made narrower. Either way, I think the main problem is that neither the British nor the French would want to join forces; in order for this to happen, one of them will end up being very sad. $\endgroup$ Commented Nov 16, 2015 at 20:49
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    $\begingroup$ Would a divergence at late 16th century be acceptable? Henry of Navarra and Elizabeth I were allies until Henry became catholic in order to become king of France and then married Maria de Medici which made the Bourbons more or less permanently catholic. Being as Elizabeth did not have an heir she liked and Henry was hated by catholics even after conversion, an alternate path where Henry skips conversion and marries an English woman of suitable bloodline might be practical. If Henry then could gain the French throne anyway. You can do a catholic variant of the same bit later in early 17th. $\endgroup$ Commented Nov 16, 2015 at 21:01
  • $\begingroup$ @VilleNiemi "If the facts don't fit the theory, change the facts"? ;) $\endgroup$
    – user7076
    Commented Nov 16, 2015 at 21:09
  • $\begingroup$ @PhilipRowlands Yes! Always remember: on Worldbuilding.SE we traffic in counterfactuals all the time. $\endgroup$ Commented Nov 16, 2015 at 21:31
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    $\begingroup$ What Bill said. It is your scenario, why get stopped by the pesky details when you can just change them? $\endgroup$ Commented Nov 16, 2015 at 21:38

3 Answers 3


Two words: The Hapsburgs (or Habsburgs)

The Spanish branch of the Hapsburgs was behind the infamous Spanish Armada, defeated in 1588 by the plucky Sir Francis Drake. That was the high point of Spanish Empire. After that, everything was in slow retreat.

The Hapsburgs didn't just rule Spain at the time. It was also what is now Germany, Austria, Hungary, Czech Republic, Romania, The Netherlands, Belgium, Switzerland, and parts of France and Italy. Click for a nice map from wikipedia.

Ok. So, lets do some more history editing to get you where you want: Lets say England did turn back the Spanish Armada in 1588, but at a high cost and with the Armada largely intact afterwards. Lets also say that The Hapsburgs soundly defeated the dutch revolutionaries in the 17th century. Not only is the Netherlands still in their possession, there's no Dutch Golden Age where they became, for a while, one of the dominant sea powers globally. In fact, lets say they managed to hang on to everything, including Portugal - so another future global sea power is not on the international stage.

Bonus points if your Hapsburgs also figure out how to avoid all the inflation from the silver and gold which flowed in from the new world got dammed up by their mercantilist policies, and the genetic corruption from inbreeding.

So, all these bullets dodged taught the Hapsburgs a lesson on strength and avoiding decadence. So, they spend the rest of the 17th century unifying their family's two branches and developing a world class system of government bureaucracy - think mandarins - to keep all these far flung territories under their control and operating smoothly.

Meanwhile, Britain, the only other possible sea power, is struggling to build the navy and colonies they had in the real history. They're butting up against Spain all the time, and Spain is having a jolly time depriving England of the best colonies and chasing down her privateers. France attempts to build up sea power & colonies as well, with similar results. France is also happens to be surrounded on all sides. So, France has the motivation of the Hapsburgs, and their example, to unify and rationalize their own political structures; including equalizing the hated gabelle -- the salt tax that was mindlessly absurd in its implementation, and was a major source of grievance leading to the French Revolution in its own right.

So, no French revolution in sight, and the country is operating efficiently and has the same goal as Britain: take more colonies from the Hapsburgs.

Ok, so by the mid 17th century, you have a Hapsburg super power, and two great powers that are struggling for every advantage against the Hapsbug Empire, and thus are internally unified and militarily developed. Then a new Hapsburg emperor ascends the throne, and decides that the best way to end all this annoying chipping away at Hapsburg colonies and looting Hapsburg shipping is to solve the problem at its source -- in the French and British homelands. He invades...

So there ya go. One tailor made scenario for Anglo-French alliance. :)

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    $\begingroup$ Incidentally, I think this scenario results in an alliance of equals -- with Britain focusing more on navel war and France, of necessity, focusing on land war. From there you can take it any direction you want -- which then leads you to an answer for you other question, on language. $\endgroup$
    – Patches
    Commented Nov 16, 2015 at 23:11
  • $\begingroup$ Also, I totally think you should have Britain have her american colonies -- which then are the breadbasket of the allied armies. Also, can you imagine a young George Washington leading troops over the Pyrenees, and a Benjamin Franklin sent by His Majesty the King of England to the courts of the Ottoman Sultan to persuade them to join in on the side of the allies? :-D:-D $\endgroup$
    – Patches
    Commented Nov 16, 2015 at 23:16
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    $\begingroup$ Of course when the Hapsburgs invade England and France, the German Principalities, Kingdom of Denmark, Sweden, Russia and many of the Italian Kingdoms outside of Hapsburg domain will also be forced to chose sides. Pass the popcorn, please..... $\endgroup$
    – Thucydides
    Commented Nov 17, 2015 at 3:07
  • $\begingroup$ The 18th century has seen several alliances with allies switching sides occasionally, e.g. in the Diplomatic Revolution. A strong common opponent (re-)raising is a good, maybe the only good explanation for an Anglo-French union in trying to keep the Balance of Powers. Spain or the Habsburgs are a natural choice. Also remember that England and Scotland united at the beginning of the century, after having been under one crown for a hundred years, and another hundred years later Ireland joined – so even with an alliance or personal union early on, a single state would take some time to form. $\endgroup$
    – Crissov
    Commented Nov 17, 2015 at 10:04
  • $\begingroup$ I never thought of any of these. Looks like this might well be my answer. $\endgroup$
    – user7076
    Commented Nov 17, 2015 at 10:59

The best way to have an Anglo French Empire is to go even farther back in History, during the 100 Years War. The English had a claim to the throne of France, and while they lacked the military and financial resources to actually conquer France, there were a few occasions where the French were ready to throw in the towel, and at one point had offered a French Princess to Henry V.

If the French had collapsed due to their internal feuds, or Henry had taken the French Bride and crown (and the rebellious French gone along with this), then there would have been a Lancasterian Empire in the late 1400's joining the two lands.

The contrafactual history at that point becomes rather murky, since so much would have changed. The English lords and merchants would probably have gone wholesale to France, as it was richer and had direct access to the continental markets, leaving England to be more of a backwater. The incredibly powerful Lancasterian kings would probably have squelched the development of a Parliament, along with many other institutions that we take for granted as part of our English inheritance. The reformation might not have happened either, or the Thirty Years War become a much shorter conflict, since the Catholic Lancasterian Empire could have provided many well trained armies to ravage the German principalities and crush Protestantism.

We also would never have herd of the Stewarts, Tudors or other royal houses in England (no Henry VIII or Elizabeth Gloriana, for example), while the French royal houses would also have been extinguished. The conditions for the French Revolution would not have taken place, and Napoleon would be, at best, an artillery officer in the Lancasterian Army. Of course no Dynasty lasts forever, but the replacement dynasty would probably not include figures like William of Orange, the Hanoverian "Georges" or anyone we would recognize in our timeline. As well, the conditions for the Glorious Revolution or the settlement of the American Colonies would also be different or extinguished; certainly an more land based Lancasterian Empire would not have developed along the lines England did, nor would there be any modern United States.

Cobbling together an Anglo-French Empire in the 1700's would be a much more difficult proposition, but Patches has done a remarkable job, so you have at least two contrafactuals to work with.

  • $\begingroup$ This is the only really historically plausible time for such a union. $\endgroup$ Commented Nov 17, 2015 at 4:12
  • $\begingroup$ I would love to read a story about the second-order counterfactuals in this scenario. Oh so many story hooks! $\endgroup$ Commented Oct 15, 2020 at 16:06

I think you should get around the issue of trying to arrange a natural alliance between England and France. They were at each other's throats for centuries. Not very likely in a real world scenario.

Instead, consider this:

1. The one country conquers the other.

The victorious king takes a queen from among their nobles to gain legitimacy (forced marriage). Then that monarch can impose all sorts of rules:

- Create a single kingdom

- Ban one language, etc.

2. A mutual enemy

An alliance (that did not historically happen) is forged between the Turks and nation X (Spain, for example?). They support a military Turkish campaign in the East, while their armies - with Turkish janissaries fighting beside their own troops - attack France and Italy (Rome is laid to waste, etc).

The French & English decide to ally in the face of their powerful, common enemy. They overcome the threat, but at a great cost: a large number of nobles from both countries are killed, including one of the monarchs. In the power-vacuum that ensues, a political alliance is forged, and a new kingdom is born, sworn to overcome their past differences in order to safeguard the Christian world.

(this could have happened in the past from where your story starts, so that you would be able to forge your own story from there on).

The possibilities are endless.

  • $\begingroup$ "The enemy of my enemy is my friend". Spain, or Prussia/Germany, would be excellent candidates for a common enemy. Both France and Britain regarded Spain as a rival for colonial wealth and control of trade routes through the Mediterranean Sea, Bay of Biscay, English Channel etc. The biggest hurdle would be explaining how the two countries put aside their religious differences; France was largely devout Catholic until the French Revolution, while England was the first entire country to declare non-allegiance to Rome. $\endgroup$
    – KeithS
    Commented Nov 17, 2015 at 22:08

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