I'm always surprised at how little Roman Empire-inspired fantasy there is

Yes, I know about Codex Alera. And probably the other two things you were going to mention. But there is a reason everyone always mentions those: there is an extremely limited amount of fantasy that's based on the Romans in the same way ASOIAF is based on (a somewhat misguided idea of) medieval England, or how a growing number of books are fantasy takes on varied Indian, Chinese, Middle Eastern, etc. kingdoms (you know the ones).

It is particularly surprising because, specifically in the case of epic fantasy, which is very much concerned with sprawling empires with vast armies and awesome conflicts, and which has very much been dominated by European writers (and occasionally their tax dodging cousins across the pond), one might, or indeed would, expect that the OG sprawling European (well, Mediterranean, but why quibble?) empire would receive a consequential amount of attention.

But I suppose Tolkien happened and really shafted us testudo enjoyers. Perhaps if he'd written Lord of the Togas instead...

I also notice the other major European land empires don't get much love: Charlemagne's, the HRE, Napoleon's pan-European alliance. The HRE is a clusterfuck, so that's understandable (yes, I know it's The Witcher's Nilfgaard); and fantasy has been allergic to guns till recently, although that's changing (I also know about Témeraire and Strange & Norrel). But who the blazes doesn't want to see Charlemagne on a dragon roasting some Saxons?

If you mention Malazan I'll throw a pilum at you.

EDIT: Forgot to add: There's a good 1000 years of material before the fall of the West, more if you count the Byzantines, but 200 years of Anglo-French history get all the love. SMH.

EDIT 2: I don't know what that seal means, but thanks I guess.