When I write lore for the campaign setting, my main goal is to NOT over specify everything. I have to fight back the urge to write tomes upon tomes of flavor and history. In the end, I want the game to be open ended for the players to decide their place. I don't want to have races or ethnicity or classes railroaded into my Vision. I'd rather keep it vague and poorly defined and let it become more concrete through actual play.
The lore will be written from a "human" perspective. What I wrote in the entry for the Dwarf race is a good example, I hope. It covers a period of over 2000 years (~1000 BC to 1600 AD) very briefly and is limited in perspective. Ultimately, there would be nothing written and very little myth from farther back than that outside of the ancient cultures in Egypt, Mesopotamia, and China.
I'm also writing with the assumption that there is a certain level of general knowledge of our shared, actual history and geography. While I know that is not the case, I will try my best to make it transparent during game play.