I think that misses the point (or at least my point). Yes it was warmer then. But it was even warmer 50 Myr ago. For example one thing that sets the two periods we are discussing apart was if Antarctica had glaciers at all or not.

The Climate heading in this article will give a little overview https://en.wikipedia.org/wiki/Cenozoic

See also the plot here https://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Therm...