@Carp, thank you for yet another amazing update. Although I like your focus on Corsica and conservative approach to butterflies it is really interesting to see some wider divergences from time to time.
While I am by no means a specialist on the Seven Years War, I do think TTL variant is very plausible and eagerly await for future developments (as many people have already commented there would probably be changes all over Europe, although many of these changes could still diverge to close to OTL outcomes ) .
I do however have two cents to add on the topic of East Prussia.
My statements are heavily based on a 2014 work by M. Anisimov (who is specializing of Elizaveta Petrovna’s Russia foreign policy and has a bunch of works on the subject) “EAST PRUSSIA IN RUSSIA’S MILITARY PLANS DURING THE SEVEN YEARS’ WAR (1756-1763)”.
Here is the full text of the article in Russian (unfortunately I was not able to find an English translation, so you have to either trust me retelling it or use google translate).
The issues mentioned in the previous discussion were dealt with in the article, so I will give M. Anisimov’s answers to them (and add some my own perceptions):
I.
On East Prussia: My impression is that despite the original plan to swap East Prussia and Courland, Elizabeth forced the locals to swear allegiance to her and otherwise hinted that she might just keep East Prussia. Accordingly, ITTL Elizabeth held on to the territory during the last year of her reign.
Quoting the article: “Many studies overestimate the importance of East Prussia’s inhabitants swear of allegiance to Elizaveta Petrovna and treat is as a sign of a final decision to annex the province. However in 1742-1743 the population of the whole Finland was also forced to swear allegiance to Elizaveta Petrovna which did not prevent the empress to return by peace treaty the overwhelming majority of Finland to Sweden”.
This example IMHO shows that swear of allegiance does not guaranty the determination of Elizaveta Petrovna’s government to keep the territory no matter what.
More importantly, however, is the text of special declaration to Russian-Austrian convention of March 22, 1760 (which is more than a year later than East Prussians swear of allegiance in 1758) states (again, summarizing from the article):
Duchy of Prussia shall be given to Russia as a fair compensation for the losses caused by war (conditional on Austria recovering Glatz and Silesia). Russia is committed to stating negotiations with PLC for “resolving East Prussia’s question to mutual benefit” and Maria Theresa guaranties to support Russia in these negotiations.
The Russian desire not to keep East Prussia, but to exchange it is further confirmed by Russian missive to Marquis de l’Hopital of February 2nd, 1761: “…and thus Russia intends to exchange East Prussia with Poland after negotiations with Warsaw.”
To sum up despite the swear of allegiance Russia never intended to keep East Prussia, it was only a bargaining chip to get adequate compensation from PLC. This proposed schema was a part of official declarations and diplomatic messages and was either officially supported by Russia’s allies ( by Austria) or accepted (by France).
ITTL peace treaty is signed in October 1760, and Elizaveta would have more than a year to strike a deal with Augustus. So it looks like by the start of Peter III’s rules the exchange would already have been made.
II. Another important question is what territories Russia would get from Poland as a compensation for East Prussia. Usually Courland is mentioned sometimes with Polish Livonia (Lettgallia).
What looks weird is that this exchange is very much in favor of PLC:
While East Prussia is considered a poor province by German standards, in 1760 it probably has around 700 thousand people (1 million in 1807;
source) and more importantly East Prussia controls the mouth of Neman (Memel) and has some control over mouth of Vistula (Marienwerder and its area on right bank of Vistula before splitting, Pillau and Konigsberg control Vistula Lagoon aka Frisches Haff control several branches of Vistula) – thus threatening both Polish and Lithuanian export. Additionally Konigsberg is a large (50000ish) and rich city.
Courland probably has the relative wealth close to East Prussia's but is much smaller (population grew from 210 to 290 thousands over XVIII, so probably around 250000 in 1760s;
source), Lettgallia is relatively more poor(as are other territories mentioned below) and has around 150000 popultion (grew from 103 to 190 thousands over XVIII;
same source). The strategical importance is incomparable: while Daugava is important for trade, Polish magnates export almost exclusively by Vistula and for Lithuanians Neman is more important than Daugava (especially since Russia controls the latter’s mouth at Riga anyway).
On top of that Courland is not even part of PLC-proper. It is a vassal over which PLC does not have any real control (and Russia does have a lot of control over Courland through Biron's family). While officially recognizing the de-facto situation that Courland is Russia’s, not PLC’s is extremely important, its value cannot be compared to the value of East Prussia even if PLC adds Lettgallia to the table.
I personally was always puzzeled why Russia (which has just proved its military might and that has a very considerable influence over PLC up to a point that it can almost be considered Russian dependency) would be willing to make such a disadvantageous exchange with unarguably much weaker PLC.
M. Anisimov’s article provides me an answer for this paradox.
He writes that Russia did not expect PLC to part with just Courland. He claims that Russia wanted to additionally annex border territories in Belarus and Ukraine. He also quotes to documents shedding light on Russian plan:
“…[Russia] shall take not only Courland but such a rounding of borders from Polish side that not only numerous troubles that are present would be resolved, but also we would obtain a possibility to connect Baltic and Black Sea trades and by this receive a fair share of Levantine trade”.
Connecting Baltic and Black Sea trade heavily suggests securing Daugava and Dnieper. This perception is further secured by another description of desired territories:
“provinces adjacent to Smolensk and Pskov regions”.
Now let us look at the
map of PLC and find such provinces: these are Polish Livonia, Polotsk, Vitebsk and Mstislavl voivodeships and part of Minsk voivodeship on the left bank on Dniepr (to the south of Mstislavl and North of Chernigov).These territories also match first the describtion: Russia becomes the controller of both banks of Daugava, of the Left bank of Dnieper all the way to the Crimean border and also controls the land between those two rivers (thus allowing for connection of Baltic and Black sea trades).
Now combining this with recognizing the de-facto situation of Courland being part of Russia creates a treaty a much stronger party forces upon much weaker.
Next a question has to be answered if the disparity is too much and Augustus and Sejm would reject it outright?
I have already analyzed the value of East Prussia. Now let 's analyze the value of Russian claims.
Courland as is already mentioned has around 250 thousand people but is not de-facto controlled by PLC.
Regarding other territories we ironically have a good estimate of those. Let us look at Russian
gains by First Partition in 1772 interestingly enough they are almost exactly the same as the demands described* (which can be seen on
this map). Thus we know the population of the described territories: 1.3 million people in the Russian part of First Partition and 190000 in 1790 in parts of Polotsk and Vitebsk voivodeships retained by PLC. We can approximate the total population of these territories by 1.3 millions combined (and 250 thousands in Courland).
The relative wealth of these territories is definitely smaller than that of East Prussia.
*IMHO that may allow us to conjecture that Russia annexed the territories it had designes 10 years previously; that attempt was blundered by Peter, but the plans remained but for Courland and two small parts of Vitebsk and Polotsk voivodeships
Now this is of course still a treaty that favors Russia. In my opinion it can be accepted by following reasons.
1. Russia obviously has leverage over PLC: military leverage(undoubtfully), diplomatic leverage (Maria Theresa pledged to support Russia in the negotiations) and political (Russia has a lot of clients in PLC Sejm)
2. The described previously strategic importance of East Prussia for securing export grain trade. Also worth mentioned is that people who most profit from this trade are also the ones who make the decision.
3. Augustus III can also benefit from this greatly. Potentially East Prussia (or more probably some part of it) given to him or to his son. Not only it would increase his personal power in the realm, it will also give him German-speaking personal vassals in PLC borders. For German prince such as himself it can be important.
Also Russia probably provides additional guaranties of his son election, and having more guaranties cannot hurt.
4. Maybe Russia can also pay monetary compensation to PLC to sweeten the deal (and these money would probably be effectively split between the decision-makers as legalized bribes)
To sum up:
a. Russia was absolutely determined to swap East Prussia for Polish territory and made declaration about it long after the swearing of allegiance (also Finland precedent reduces the importance of allegience).
b. Since after the war end Elizaveta has more than a year to implement swap, she will probably be able to do this before Peter gains the throne, so his thoughts on East Prussia become less important
c. Getting just Curland (or even Curland and Polish Livonia) is a very weird move since it greatly influences Poland. There is evidence that Russia intended to gain Courland
and territories close to Russian part of First Partition.
d. While such a deal obviously favors Russia there are arguments why such treaty can be accepted. While IMHO it is not guaranteed it would not be implausible either.
P. S. Sorry for such a wall of text. I wanted to prove my point as detailed as possible. Hope it isn’t too much