Legionary umbones...

[Tim Edwards]

Of course!

That's pretty unequivocal, albeit on an oval shield.

Perhaps Caius Valerius Crispus is the most famous example, though I'm starting to wonder whether he is the exception rather than the rule.

I still find myself wondering how common rectangular shield and boss combinations were in the first century, given the scant evidence compared to the rounded type.

I'm beginning to wonder whether the sub-oval shields and rounded bosses commonly depicted carried by soldiers and guardsmen serving in Italy during the first century were equally prevalent in the Rhineland...