A major bane to historians and alternate historians are historical misconceptions. This false common knowledge can prove an issue in timeline writing and discussion. Some of these can be minor and forgettable. Others, massive issues.
The following is a list of examples of historical misconceptions, with the truth summarized below them.
1.) People in the Renaissance thought the World was flat/Columbus and his financiers feared the world was flat and his voyage proved it wasn't: People had known since the ancient Greeks the world was round, and everyone knew it. Simple things like the Earth's shadow on the moon and the fact that things disappear over the horizon are easy enough to pick up on. The Europeans weren't afraid to fund Columbus because they thought he'd fall off the Earth; they were afraid because Columbus thought the Earth was actually only one/third of its actual size (and take into account they knew the approximate size of the Earth already, so either he was rather dim or was just trying to sell his idea) and no one had gone out that far into the unknown before, so few believed he'd reach Asia. Columbus' journey had nothing to do with the shape or size of the Earth, and certainly didn't prove it was round. This myth began when it was included in a biography of Columbus by Washington Irving which mixed facts with historical fantasy. The fact that this myth continues in text books based on the misconception that that biography was totally factual is one of the top 10 reasons we should stop relying on Texas for our text books.*
2.) Hitler was a vegetarian: Many have reported seeing Hitler eat meat. The likeliest reason Hitler avoided meat when he did was not due to vegetarianism, but simple health issues. Hitler was said to have intense stomach pains, but refused medical treatment for it. Amending his diet in an attempt to cure himself, he boiled it down to cheese, grain, dairy, vegetables, etc.
3.) George B. McClellan ran in 1864 on a platform of ending the war: McClellan wanted to continue the war, and wanted this during his run for the Presidency. It was the Democratic party itself that said he was running on a platform to end the war with an armistice with the South. This, of course, led to problems as the party was saying one thing and McClellan another.
4.) Sitting Bull killed General Custer: Sitting Bull was far to old to be involved with the battle at all, but he was the tribes' holy man and predicted the enemy would be delivered into their hands.
5.) Jimmy Carter was the first Southerner elected President since the Civil War: This pops up time to time from simple forgetfulness of the hectic political landscape of the 1960's and 1970's. The first Southerner elected President since the Civil War was Lyndon Johnson, elected to his own term in 1964. That is, of course, if you don't count Virginian born Woodrow Wilson. (The confusion arises because Carter was the first President from the Deep South since the 1840s, but not from the South altogether).
6.) Lyndon Johnson succeeded JFK, but was never elected to his own term: See number 5. Johnson was elected in 1964. He did not seek reelection in 1968. This occasionally pops up; again, most likely forgetfulness.
7.) Betsy Ross sewed the first American flag: This story was made up by her grandson, William Canby, who first told it before the Historical Society of Pennsylvania in 1870, claiming his grandmother had told it to him on her death bed when he was 11 (Ross had been dead for 36 years at this point). There's absolutely no evidence Ross sewed the first American flag, and much to the contrary.
8.) Thomas Edison invented [Insert Invention Here] and holds the most patents of any American: Thomas Edison was notorious for his thievery and under-handiness, frequently stealing from those scientists and craftsmen working at his Menlo Park lab. Most of Edison's great accomplishments were in the business realm, as the man was quite dim as a scientist – the reason his inventions took so long was because he would not look at past studies and research, and thus went over the same mistakes that others had and did not see any improvements based on earlier research. The majority of his patents were not new inventions, but simply improvements on earlier ones. The light bulb had already been invented in the 1830's; Edison was just looking for a way to make it longer lasting and more reliable, and ignored previous research in doing this. The motion picture itself was something created by one of his underlings; Edison had no interest in the idea, and only later, after it became successful, took it over and stole the glory and credit. Edison also had some of his men copy prints of the French silent classic “Le Voyage dans la lune” (which the French were planning to distribute in the US), distributed them himself, and made all the money from the US distribution thanks to loose copyright laws. He did probably invent the phonograph, however.
Perhaps most infamously, Edison screwed over and ruined the career of an actual scientific genius, Nikola Tesla. Edison hired Tesla to redesign his electrical generators, which he did, and when Tesla asked for his promised $50,000, Edison replied “Tesla, you don't understand our American humor”. Tesla then shopped around the idea of alternating current against Edison's direct current. Angered that the man he screwed over would dare try to go against him, Edison started a smear campaign against alternating current, which was much more efficient and economical than direct current. To do this, he would pay neighborhood children for their pets and promptly electrocute them to death with alternating current, and lobbied to have the first electrical chair use alternating current. Guess which electric current we use today? So the valiant American wizard was actually a douche who stole most of his credited inventions, fluffed up his patent count with simple improvements, screwed over inventors left and right, and killed animals.***
9.) John F. Kennedy was the youngest President/Teddy Roosevelt was the youngest elected President: The youngest President was Theodore Roosevelt, who was 42 when inaugurated in 1901. However, he assumed office upon McKinley's assassination, and thus was not elected at 42. John F Kennedy was the youngest person ever elected President. These two get mixed up fairly often.
10.) Paul McCartney was the leader of “The Beatles”: The Beatles were always a democracy of sorts, so there was no official leader. But if one of them had to be declared the leader, it would have been John Lennon. Lennon had formed the group, its forerunners, and was the constant throughout all variations. He was also the one who basically got everyone else on board. The misconception comes from the time after Brian Epstein's death. Epstein, the manager of The Beatles, had held them together. After his death, cracks started to appear. Paul McCartney, attempting to make things better, tried to fill Epstein void by trying to assume a leading role. It was with that that he further alienated his fellow band mates, and this would eventually help the collapse of The Beatles. So pre-Sgt. Pepper's, the leader was solidly John with Paul not even close to qualifying. It was Sgt. Pepper's and afterward that Paul would try to become the leader.
11.) The Army of the British Empire was massive: The Army of the British Empire was surprisingly small compared at least to what many may think it would be. During the 19th century, its size ranged from a few tens of thousands to perhaps a few hundred thousand (the latter generally ballooning to said size during war time; the peak of the 19th century being the Napoleonic wars with a British army of 250,000). During the latter 19th century, there was an average size of something like 30,000 soldiers patrolling the whole of the Empire at a time.
12.) Jimmy Carter was a Liberal/Sissy/Ruined the economy: Jimmy Carter was a Southern Evangelical governor turned President who began the process of deregulation before Reagan. In 1978, he deregulated airlines; by 1980, he was deregulating trucking, railroads interest rates and oil. Carter also gave the wealthy a capital gains tax in 1978, giving them their first tax cut in 15 years. He set into motion the mechanisms of deregulation later to be used by Reagan. Concerning sissyness, Operation Eagle Claw, the plan to rescue the hostages A-Team style, was extremely ballsy. The economy was already screwed for whoever was President from 1976 to 1980 due to post-Vietnam economic fallout such as inflation and the gas crisis, and the second gas crisis that would cripple the economic recovery that had been moving along. Had either Reagan or Ford been in office, they would have faced the same situation and been equally at its mercy.
13.) George H. W. Bush ruined the economy/was a sissy: Bush was dealt a bad hand of the post-Reaganomics recession. While he could have perhaps handled it better, he was not the cause of it. Concerning sissyness, Bush was a war veteran who served as a Navy aviator during World War 2. It should also be noted that he toppled the Noriega regime in Panama and defended Kuwait during Desert Storm.
14.) “Soviet” can describe anything Communist: “Soviet” is a Russian word for Council. It requires the formation of a Communist Russia or Eastern European state, and is unlikely to appear in a power not using the Cyrillic alphabet. Calling foreign nations “Soviet *Put Name Here*” is like calling the US the “United Государственные of America”.
15.) Ninjas wore black: Ninjas were geared for stealth. Because of this, they often wore disguises and costumes. However, even at night, black was not worn as dark blue would be a better color. This misconception comes from the threatre where, as the back of the stage or curtain would be black, an actor playing a ninja would dress in black to be able to jump out of the background and shock the crowd.