How do historians know the details of a seemingly private event?

Question

Sometimes I read in history that someone said something, but it seems, it's just a daily conversation, or even in private, or a secret event. So how do history writers know these details? It seems impossible, e.g. when there are only two people, and one of them killed, and then the conversation between them was revealed to history. But similar situations can be met many times. Maybe the history writer imagined or invented those things? That is the only possible scenario, isn't it?

Answer 1

History is, by and large, the study of documents. Everyone loves a good story, and there have certainly been historians in the past that have taken advantage of that by developing grandiose narratives that have little grounding in what actually happened. Take for example Julius Caesar, the man who spoke 40 languages, overcame armies of one hundred thousand or more with only 30,000 men, and was never defeated in battle through fault of his own. We, of course, know that those statements are nothing but hyperbole but Caesar, when writing his own histories of himself, took advantage of the natural human desire for a good story. Caesar was writing in a way that could be dramatically read to the Roman people in the forum to raucous cheers. Historians today know that much of what Caesar wrote was inflated and dramatized to increase his own standing, they learn this through the reading of correspondence between commanders and logisticians, personal diaries by other commanders and soldiers, and through careful cross referencing of accounts of oral stories that were passed along and written down. History is about filling in the gaps with evidence. While we can never truly know what Julius Caesar or Henry VIII said behind closed doors, we can wager to guess based off of multiple accounts of what they said. If there is a clear conflict, then we know the author was at least partially fabricating what they wrote. When there is consistency, however, we are able to pinpoint details that paint a clearer picture of the events that transpired by connecting those details to larger historical events or even contemporary events that would have informed the conversation. Documentation by people who were there survive to this day in the form of letters, diary entries, notes, and fragments of parchment that can be put back together. The historian's job is to transcribe and transmit that information to the reader so they may better understand the events of the time in which those original documents were written.