Has it ever happened before?

In the 64 team era, has it ever happened that all four #1 seeds failed to even make the round of eight?

If it has, I sure don't recall it.

 

The CBS talking heads just confirmed this is the first time.

 

Imagine if we’d lost to Xavier—none of the #1 or #2 seeds would’ve made it.

 

That's why they call it "March Madness."