Historical Alternate

These are the most common type of "alternate Earth", where some specific "for want of a nail" event during the past 4-5 thousand years split the trousers of time. Often, the precise point of divergence is obscure, it's the outcome that matters. It's easier to say "Edison became a journalist and newspaper editor, rather than inventor" than "Edison's father had a good job in Ohio, so he never moved to Michigan, and Edison's schooling was different and he developed an interest in writing", and that's easier than "Edison's father's boss won a contract he lost on Baseline, so he could pay Edison's dad more", and that's easier than "The competitor who would have won the contract was hit by a stagecoach and missed a vital meeting", and that's easier than "A butterfly startled a wasp, which stung the horse pulling the stagecoach, causing it hit the competitor."   See, it's always the butterflies.