-Nelson caught the French expeditionary fleet to Egypt at sea and defeated it in battle. Napoleon Bonaparte (1769-1798).
Fatherland by Robert Harris and SS-GB by Len Deighton are both terrific takes on the question “What if the Nazis won WW2?” Quite different books, though. Elleander Morning by Jerry Yulsman is also very, very good. A young Adolf Hitler dies in Vienna and WW2 never even occurs!
For other points of divergence, I’d go with the Chinese admiral Zhang He being much more widely-traveled and successful than he was in our timeline. Or have the Lost Colony of Roanoke Island thrive and expand. Or have the Divine Wind not save the Japanese from Mongolian invasions. Or have George Washington’s surprise attack on Trenton go badly awry. Or have Napoleon win at Waterloo (or conquer Russia, or invade and occupy Great Britain). Or have the Japanese win at Midway.
The possibilities are endless.
Although it’s not revealed until the last book,in Randall Garrett’s Gandalara series the lead character ( a man of our world who awakens in the not-quite-human body of a man of Gandalara ) :
Discovers that in fact, Gandalara the “Walled World” is not some other world, but actually the bottom of the Mediterranean millions of years ago when it was dry. The Gandalarans are a primate species that evolved, lived there and were destroyed when the Mediterranean filled, without modern people ever discovering they existed. He’s been drawn back in time ( right at the period when the Mediterranean begins to fill again ) to somehow prevent this, and in doing so create a new timeline when humanity ( of a sort ) walks the world millions of years early.
Nitpick, the cigars and battle plan were found before Antietam.
Yep, and the battle that ended the war happens at Camp Hill in the first chapter. That series is about the political aftermath much more than the war.
Others from Turtledove without a WWII or CW theme:
Ruled Britannia, as mentioned.
The Two Georges written with, no kidding, Richard Dreyfuss
[spoilers]George III and George Washington worked out their differences 200 years ago and in modern times North America is part of the commonwealth.[/spoilers]
Other cool Alt-History of which I approve:
Lest Darkness Fall, L. Spague DeCamp
[spoilers]A modern man back in time uses technology to prevent the fall of Rome.[/spoilers]
1901 by Robert Conroy, as mentioned. He also wrote 1862 where the US has to take on England as well as the CSA and 1945 which details the invasion of Japan.
In fact, here’s the Uchronia list from points of divergence. It starts at the beginning of the solar system and works its way forward. Good luck with that.
There’s the Germanicus trilogy: Procurator, The New Barbarians, and Cry Republic, written by Kirk Mitchell. It’s set in essentially current days, but in a world where Rome never fell. Christianity is a minor (but possibly growing) Eastern cult in the first book; Rome is just now exploring the New World and encountering the Aztecs (they’re the barbarians referred to in the title) in the second.
Gibson and Sterling’s The Difference Engine, featuring a Great Britain in 1855…over twenty years after the beginning of Charles Babbage’s computer revolution.
In other words, a Steampunk Speedball. 
The ending is a little…hard to grasp, and the plot wanders a bit, but all in all it’s a hell of an expedition through the alternate world.
Although, I have to be honest, a Civil War is mentioned in the Americas, it’s not that much of a plot point. More like background detail.
Nitpick:
Piper’s “Paratime” series, which includes “He Walked Between the Horses” (mentioned upthread), Lord Kalvan, and four long short stories, is set in a multiverse where one timeline has discovered the technology to cross timelines, and studies and sometimes exploits the others, or at least as many of the others as suits them. The stories center, at least mostly, on the adventures of Valkan Varr, head of the Paratime Police whose duties include keeping the exploitation of other timelines within what the one timeline that can travel across them considers moral, and, overarchingly, to protect the secret that crosstime travel is possible and one timeline has it. Lord Kalvan’s premise is that a Korean War veteran (and military history geek), Calvin Morrison, who is a Pennsylvania State Policeman in, essentially, our timeline, gets transported by a side effect of the crosstime field into a timeline where the Indo-Europeans, instead of moving west into Europe, headed northeast across the Bering Straits into America. He builds himself a multilayered cover story to account for his presence, and, in time-honored fashion, ends up marrying a petty king’s daughter. Normally the Paratime Police would find a way to eliminate anyone who might guess the Paratime Secret from having been an accidental crosstime transferree like this, but it takes them time to figure out that Calvin/Kalvan had been transferred, and his cover story is good enough that they decide to leave him alone and study the crossfertilization of ideas instead. Piper hints but never actually comes out and says that the reason for Kalvan’s inadvertent transference across timelines is something Verkan himself is responsible for – he’d eliminated and covered up the introduction of a feral ET hunting beast into our world’s 1954 Pennsylvania, and it’s implied that it was the effect of his ‘time machine’ that transported Kalvan. (The hunting beast incident is in one of the related short stories.)
There is also a sequel to Lord Kalvan called Great Kings’ War co-written by John Carr after Piper’s suicide, which is substantially better than the usual ‘good story continued by another author’ tripe.
The Ghost series has a North America where the Dutch colonies were more successful, and the political divisions ended up quite different. The French are still there, Texas is an independent republic, as is the state of Deseret, Canada and some of the northern colonies are British. I believe Modesitt is a Mormon, and Deseret comes up a few times in various books as an independent state. The divergence is obviously a century or more before the traditional Revolutionary War one.
The technology and culture is quite different too. Difference engines (computers), steam cars, some mentions of odd fashion, class setup and traditions are more like 19th century models. Overall tech level seems to be steampunkish.
Kim Newman has written some great alternate histories. Back in the USSA (co-written with Eugene Byrne) has America rather than Russia turning Communist in 1917. His Anno Dracula series is an alternate fiction: he has Dracula beat Van Helsing and follows his subsequent history through the 20th century.
In the children’s room, Joan Aiken’s excellent Wolves Chronicles take place in an England where the James II was never deposed–the Scottish James III is on the throne, and the Hanoverians are always plotting to take over the kingdom.
A Muslim victory at the Battle of Tours would be interesting. All of Europe may have been Muslim within a century.
If Otto III, the Holy Roman Emperor, had lived to marry the Byzantine princess Zoe (he died en route to their wedding in 1002) it would have united much of what’s now Germany, parts of France, large parts of Italy and bits and pieces of other lands with Turkey, Greece, and huge chunks of western Asia and Eastern Europe to create an empire greater than Charlemagne’s. Had they produced a capable son, that would have forever changed history.
I’ll leave it to an ancient historian to figure the exact point of divergence (Constantine perhaps), but if Mithraism had become the religion of the Roman Empire instead of Christianity it would be interesting not only to see how different the world would be but how similar.
Opechancanough was the uncle of Pocohontas who succeeded her father (Wahunsonacock, aka Powhatan) as high chief of many confederated tribes. He had always thought his brother had been far too lenient with the settlers, and at high noon on March 22, 1622, he did his best to remedy that in an incredibly well planned and orchestrated (for people with neither writing nor clocks nor many firearms) simultaneous attack on many villages in the Virginia colony. It’s aim was, quite simply, genocide- he wanted to wipe out the English presence in his land. He killed between 1/4 and 1/3 of the settlers- about 350 by most counts (numbers are very imprecise).
One of the reasons that the attacks were not more successful was because of a youth named Chanco who had lived with a white family and was ordered to kill them. Instead he warned them, and they warned many others in a canoe ride and bells and other relays that allowed many of the settlers to arm. If Chanco had died, or had been loyal to his weroance, or had just run away, it’s very probable that Opechancanough would have killed far more people than he did, at very least the majority of the settlers, and then gone back and picked off the survivors or ransomed them for weapons with the incoming ships. This would be an interesting point of divergence. (Admittedly Plymouth was still founded in 1620, but the Indians in Massachusetts most certainly knew of Virginia and may have gotten ideas.)
Interesting sidenote for a possible novel is that Chief Opechancanough may have once been Catholic and lived in Europe. Some biographers speculate he may have beenDon Luis, an Indian nobleman taken back to Spain for an education by Jesuit missionaries who planted a failed colony in Virginia in the 1580s.
Romanitas is set in 2004, in a world where the Roman Empire got its act together and conquered half the world. They still use slaves and Roman gods, but maglevs are common place. There are only three Empires on the map, the second most influential being Nionia (Japan) which holds Australia up through east Asia to Japan plus half of Terranova (North America). Sina (China) is a nervous buffer state between them. And the bottom half of Africa is independent.
The PoD in The Peshawar Lancers by S.M. Stirling is a meteor strike in the North Atlantic in 1878, which causes the collapse of civilization in North America and Europe. The book is set in 2025 after 147 years of recovery. The most powerful nation on Earth is the British Empire (now centered in India not England).
There’s Keith Roberts’ Pavane, which is set in a world where the Reformation was successfully repressed and the Catholic Church reigning triumphant after the assassination of Queen Elizabeth.
Poul Anderson explored a number of PoDs in his Time Patrol short stories. The one that stuck in my mind was *Delenda Est *where Carthage defeats Rome in the Second Punic War and the Roman Empire never rises. Amongst other consequences this prevents the rise of any of the great monotheistic religions (including Christianity) and no development of the scientific method. Some bits of technology (eg the steam engine) have been developed earlier than in our timeline but there has been no systematic exploitation leading to a sort of 19th century level of technology.
Stirling’s *Nantucket *and *Peshawar Lancers *books have been mentioned but another timeline - not relying on ASBs or a giant comet :dubious: - is in Conquistador. It is not really developed - Stirling is more interested in the people from our world moving into this “empty” California - but this has an alternative universe where Europeans have never reached the Americas. In this case the PoD is the recovery of Alexander the Great from the illness (whatever it was) that killed him in 323BC. He goes on to establish a long lived empire from Europe to India and again the Roman Empire never rises.
Another “If the Reformation never happened” novel is Kingsley Amis The Alteration. In this world, Martin Luther made a deal with the Holy See and became Pope Martin I.
The PoD there is that Muhammed converts to Christianity, btw.
If you really want to go back a ways, let the asteroid that hit 65 million years ago somehow hit the moon instead or else avoid the earth and see if the dinosaurs/proto-mammals ever evolved intelligence.
Star Trek: Voyager had an episode with dinosaurs which evolved intelligence, but they left Earth and humanity evolved in their absence.
Yeah, it didn’t make much more sense on TV either: Distant Origin (episode) | Memory Alpha | Fandom