Every race “discovered” America before Columbus. Of course none of them had the sense to realize what an incredible source of wealth their discovery was...and they didn’t set up any permanent settlements...but okay they were here first.
Columbus and Co. stuck around...and that’s all that counts.
On the other hand, there's this deal involving the cocaine delivered to the Egyptians in the 1800 BC period. That's during or just before another enigmatic "Dark Age".
The 1300s seem to be a major focus for most everything involving the Mississippi Valley. The Great Mound at Cahokia was started then ~ and there's some sort of stone or stellae at the bottom smack dead center.
Lots of people want to dig down to it to see if it's got something to read ~ like Huang Chi Lu Was Here.