What if Jani Beg didn’t put infected corpses on their catapults and fling them over the defensive walls of Caffa? Would ~50% of Europe’s population still (eventually) have been wiped out by the Black Death?
IIRC Darien failed after the departure of James VII/II. One would have to assume that the benefits of its success would have favoured Jacobites over those wanting to keep the already installed Protestant succession. AFAIK the latter were predominantly the Lowland merchants and professional/upper crust who did well out of the Union under the Protestant succession. So the eventual Jacobite risings would most likely have failed with an independent Scottish Parliament as well.
Alternately, what if JFK had embraced Freeman Dyson’s idea of using atomic bombs for propulsion? Apparently the Project Orion concept of the 1960s was rejected by JFK as being too risky.
Perhaps we’d have colonies on Jupiter’s moons by now (or perhaps the mass-production of tiny nuclear bombs would have destabilised the world).
Yes, a wealthier colonial Scotland would probably have accelerated various post 1745 trends, such as the wealthy merchant Lowland class, the shift of clan chiefs from feudal barons to aristocratic landlords, and Scotland’s enthusiastic engagement with colonialism.
The Clearances probably still happen because the economics doesn’t change, but in this scenario the diaspora goes to Central, not North, America.
I strongly recommend a book I read last month that covers (in separate chapters) how the Darien scheme could have worked (if only Atahualpa hadn’t ordered a certain murder) and how the Vikings staying longer in their colony could in fact have spread Old World diseases more slowly among native tribes as well as providing them with horses and armor, meaning that, potentially, the Pilgrims could’ve been met with knights… There are lots of other fun counter-factuals in it, too.
It’s called Impossible Histories: The Soviet Republic of Alaska, the United States of Hudsonia, President Charlemagne, and Other Pivotal Moments of History That Never Happened, by Hal Johnson. He explains what really happened and how things could have been different. (Admittedly, some of what he comes up with is really a stretch, but it’s still fun.)
Thanks, I’ll look it up!
Two others:
Scotland again - When Alexander III, a reasonably popular and reasonably successful monarch, rode his horse over a cliff on the way to a tryst with his wife, his only heir was a 2 year old Norwegian princess who promptly fell ill and died. (His awareness of the fragility of the succession explains why he was riding out at night in the rain to spend some quality time with his wife - good attitude, bad execution). This power vacuum led to internal strife and misrule, followed by Edward I claiming overlordship, followed by Wallace, Bruce, Wars of Independence that lasted for c.40 years and general misery for all. So - what if his horse had kept its footing? We wouldn’t have Braveheart, we probably wouldn’t have had the Stewarts (descendants of Bruce) with all that entails for the English Stuarts, the border with England would probably be further south, etc. We might have had direct war with Edward I but wihtout the claim to overlordship based on his being called in to settle the inheritance dispute it’s unlikely to have been so thoroughly prosecuted.
From antiquity: what if Justin the Apostate had not died in battle early in his reign and instead got to continue with his programme of de-Christianising Rome? It wouldn’t eliminate Christianity but it would mean it lacked access to state power, opening up space for other religions - Manicheism perhaps - and really changing the post-Roman Empire early middle ages.
nit: Julian the Apostate 
I was actually going to suggest this in the OP. Specifically if he had taken the time to put on his armor before riding out to meet a surprise Persian attack.
One thing that might have happened as a result of this is the rebuilding of the Jewish temple in Jerusalem, which he was very keen on. Though as a way of countering Christian biblical prophecies about it, rather than as sign of acceptance of Judaism and Jewish people, however.
Oh, you’re in that timeline.
Good spot, thanks.
Not obscure, but something that a history teacher used to joke about: What if Charlemagne’s son Louis the Pious hadn’t remarried? If Charles the Bald hadn’t been born, so that Louis wouldn’t feel the need to change inheritance expectations that antagonised his other sons, perhaps the Carolingian civil war wouldn’t have broken out. The Empire could then more neatly have been split between East Francia (German) and West Francia (French). The joke then goes, no separate split in the inheritance of the descendants of Charlemagne to create Alsace-Lorraine, so no need for Prussia to take Elsaß-Lothringen in the Franco-Prussian war, so no French-German front in WW1, so no WW2 and no Russian Revolution (at least in the forms they took in 1917).
Somewhat similarly, what if Ludwig II of Bavaria had idolised the Vikings (due to the Wittelsbach connections to Denmark) instead of Germanic medieval fantasy? Bavaria would still have been beaten by Prussia in the Austro-Prussian war, but perhaps combined with seething about the Second Schleswig war against his idolised Danish relatives, Ludwig could maybe have told Bismarck to get bent when the Franco-Prussian War broke out and remained neutral. Even if France was still defeated, having a Bavarian counterweight against Bismarck using nationalism and Catholicism as arguments against joining the North German Federation, and co-religionists France and Austria backing Bavaria and other majority-Catholic länder against Bismarck, Germany might not have been united in the form that we now know. A diminished or fractured Germany might not have enabled WW1 to happen as it did or dragged on as long.
Finally, what if the Portuguese/Brazilian succession worked out differently? Either Dom João VI decides he likes the weather in Rio de Janeiro and doesn’t return to Portugal in 1820 and therefore no Brazilian independence war, or Dom Pedro I doesn’t cause scandal with mistresses leading to him splitting his attentions so much between Europe and Brazil (abdicating as king of Portugal in favour of his daughter, whose throne is then usurped by Pedro’s brother, so Pedro abandons Brazil for Portugal).
Keeping a united Portuguese-Brazilian empire for longer could have transformed the continent, with less of a colonial attitude towards Brazil as the new seat of the empire, and with the two realms treated as equals, perhaps even leading to a change of attitude in other colonial powers like Spain. Pedro I was also apparently something of an abolitionist, while in the event his successor Pedro II (in other areas a decent emperor) only got around to abolishing slavery in 1888 (and so the empire fell to coup/revolution in 1889). Pedro I with the cache of being Brazil’s liberator or the united Portuguese-Brazilian monarch, and less ridden with scandal, could maybe have gotten away with abolition far earlier.
Peter Safar was born part Jewish in Austria in the 1920’s. He was nearly sent to the Russian front. He was shot at repeatedly by snipers during World War II. And when he finally made it to the United States, he held down a dangerous “side hustle” job installing TV antennas.
What if he’d died before he did the following: invent mouth to mouth resuscitation, CPR, and the modern paramedic/EMT system? He also designed the interior of the modern ambulance, invented the mannequin (Resusci Anne) used to teach CPR, and made advances in anesthesia. (I just finished reading American Sirens:The Incredible Story of the Black Men Who Became America’s First Paramedics by Kevin Hazzard.)
In one of history’s cruelest ironies, the most liberal and reform-minded of the 19th century Czars, Alexander II, was assassinated by revolutionaries. Now he was already 63 years old and in any event his heir Alexander III was more reactionary. But if he’d lived at least a bit longer and his assassination not been fodder for hard line anti-reformists, could pre-WW1 Russia have been guided into a path where non-revolutionary reform had been possible?
One of my favorite roleplaying games is the brilliant
in which you play time-traveling enforcers of the standard timeline, protecting it from do-gooders, mad scientists, Nazis, psychic dinosaurs from an alternate timeline where the comet never hit Earth, and sentient giant cockroaches from 50 million years in the future who need humans to end in nuclear holocaust so they can evolve.
To create an adventure, you engage in exactly this sort of counterfactual. My favorite adventure involved the Bay of Pigs going terribly wrong: the United States sank the ship, the USSR launched its missiles, and cockroaches got their chance to evolve.
We tracked the timeline change down to a single moment: in 1867, Carry Nation’s husband developed an allergy to alcohol (due to a time-traveling cockroach’s judicial poisoning of the man) and stopped drinking.
Without his alcoholism, Nation never became a temperance leader.
Without her leadership, the temperance movement foundered.
Without the temperance movement, Prohibition never happened.
Without Prohibition, Joseph P. Kennedy never became a bootlegger.
Without his bootlegging, he never created the Kennedy family fortune.
Without that fortune, JFK never became president.
And without JFK’s leadership during the Bay of Pigs, the United States sank the ship.
In typing this post, I looked into it, and apparently the rumors of Joe’s bootlegging are greatly exaggerated. Still, though, it was a tremendous one-shot of a game–and with a minor tweak (Prohibition indirectly fueled the Kennedy fortune, since Joe was able to use its end to corner the scotch market), it still works.
(FWIW, we restored the timeline by staging a sacred vision for Carry Nation, in which a psychic dinosaur pretended to be Jesus and commanded her to become a temperance activist, while the rest of us were outside fighting cockroach saboteurs).
There were virtually no aerial or aquatic dinosaurs. Birds (avian dinos) are the exception. Dinosaurs were terrestrial-only creatures.
Pterosaurs were not flying dinosaurs they were flying reptiles.
Plesiosaurs, pliosaurs, ichthyosaurs, and mosasaurs were not marine dinosaurs, they were marine reptiles.
The dinosaur books that we read as kids, and the dinosaur toys we played with got it wrong. I demand restitution.
So, a typical Thursday.
One of the major effects of prohibition was nationally organized crime. This can be followed through to Mafia resentment toward Castro who removed Cube as a lucrative source of lucre for them, and then to JFK and the Bay of Pigs affair. You just need an adjustment to your timeline.
How about we go completely obscure. Introduce to each other two young fertile romantically comparable 11th century peasants who wouldn’t otherwise meet, and then let nature and the butterfly effect take its course.
Though that would take a lot of trial and error (or multiple trips back to subseqent generations with antibiotics and vitamin supplements) to ensure any of their descendants actually survive to make a difference to the future
But it doesn’t matter if that couple’s individual offspring do or don’t have surviving 20th century decendents, all that matters is that they create ripples in the time line.
It could be that their great grandson’ buys his new friend a at the logal pub drink, resulting this friend going back to sleep with his wife 20 minuets later than he otherwise would have. As a result, Hitler’s great great great… great grandmother, is now a boy.
Problem is that in my family the only person that would want to play it is me.