As an example to clarify what I mean, take the French Revolution in 1789, obviously this was a major event when it happened and people wrote all about it or preserved the facts surrounding it. The knowledge has then been passed down uninterrupted up until now. Where as with something like the city of Uruk I presume excavations in modern times is where our knowledge of these times comes from, by piecing together discovered artifacts. I assume that historians during the French revolution were quite unaware of Uruk having existed. But what about events in between, like ancient Macedonia or ancient Egypt.