I mean, sure, we have historians that document the years and everything that happened, but do we know if, in actual fact, the events may have happened a slightly different way? Or if they may have actually occurred months or even years before documented?
Just curious.
Because historians don't rely, and don't have to rely, on any single document to figure out histories. There are often pages upon pages of material that one could use to correlate the dates, from official papers to diaries and letters to church records.
Sure, there are some events that aren't as well recorded, like birthdays of people who came from humble backgrounds, but anything major is going to be written up by a lot of people who don't have reason to lie.