Webster's 1911 labelled it as an Aurochs, but that looks incorrect. Consensus is that it is a wisent?.
(Public domain image from Webster's Dictionary 1911 [full size image])
Looks like a wisent to me, but I'm not a professional wisentologist. :-)
Agreed, based on the length of the horns. Compare Google's image collections for [wisent] with [aurochs]. <>< tbc