I'm not a historian but I've recently started wondering how we "know" things about the past, and wanted to challenge my skepticism. For example, I would like to know who wrote the Iliad.
Wikipedia tells me it was Homer but I'm not satisfied. Wikipedia can tell me because someone "knew" and wrote it but they had to learn it from somewhere else and so forth.
The oldest copy of the iliad is from 1000 AD so that's just an old secondary source, but yet could the author who scribed it possibly be the source for our "common knowledge". Wiki mentions that Herodotus thought of Homer.. but how do we know that..
I'm worried that history could be filled with ancient lies and mistakes that we mistake for truth, and that we don't have the means to know better.
What you might want to read about is called Historiography. This is the history of the history I guess you could say. Schools of thought or "updates" to the type of question you asked. I am not a working historian so with that said, The Illiad was written by Homer, was recorded after already being a part of oral tradition of the Archaic period of Greece. Like many ancient texts like the Illiad or the Bible, Homer may be a composite author, or a real person. That's the objective of the field of history.
Sometimes there isn't enough evidence to definitively answer these types of questions. It isn't black and white and that's why people still study Ancient History. This applies to all areas of history. New evidence is found or old evidence is refuted, etc.