Changed history forever
People often try to fluff up the importance of an event or person by saying it “changed history,” “changed the course of history,” or “changed history forever.” (Or something along those lines, you get the idea.) There’s just one problem with that type of phrase: it’s completely, 100% wrong.
History is stuff that has already happened, or the study of stuff that’s already happened. No matter what you do today – no matter how important or how much it upsets the expectations one might have for events to come – unless you’ve invented time travel and actually gone back in time and changed the past you have not changed history at all.
What one usually means to say here is that something happened that had a major impact and events would unfold differently than one would have expected.
For instance, Abraham Lincoln “changed history” by issuing the Emancipation Proclamation. But, of course, he didn’t change history at all. He did something that had an immense impact at the time, and that would have a ripple effect that lasts to this day. It was enormously important. But, and this is crucial, he did not change history one tiny little bit. He made history, but he didn’t change it. History, as Lincoln knew it, remained the same. But the future was as of yet unwritten, and so our history is what happened as a result of his actions.
In short, “changed history” is a lazy, awful phrase. Don’t use it.