What was the role of the spatha (longsword) in Roman combat?

by [deleted]

Just in case the question is too broad, you can pick whatever time period of the Roman empire, and whatever specific context you'd like. I'd just like any clarification on the role of this sword vs. the gladius

BritainOpPlsNerf

I can't answer with confidence for infantry; but I answered a question way back that touches upon the Spatha's place in the Roman Cavalry.