Lafayette C Curtis wrote:
We don't know for sure, but given the period of the sculpture it'd be reasonable to expect a 4th-century spatha blade. This would have differed from the Windlass gladius blade by being longer (though not necessarily by a large margin), lacking the waisted profile (at most it would have had an even taper from the base to just short of the point section), and having a more lenticular rather than diamond-shaped cross-section, possibly with one or multiple fullers.
Also, very likely pattern welded by the 4th C

Alot of sword enthusiasts don't seem to understand that pattern-welding extends well back into the late Roman period. It's not just for "Vikings" and Anglo-Saxons.