Rome and (lack of) Cavalry

[rajpoot]

Also afaik there were eastern european cavalry auxilliaries stationed in England -with some evidence of their presence/garrison on Hadrian's wall (on the border with Scotland).

King Arthur and his Sarmatian knights?

More seriously though, I think Rome did not have 'Roman' cavalry because when the Roman empire rose, armies were still infantry based. Cavalry gained popularity towards the end of the Roman empire. I'd read a book by W.S Churchill once, don't rightly remember the name.....in which he attributes the rise of cavalry as one of the reasons for the Roman legions getting obsolete, and in turn causing the empire to crumble.