I've always been a big fan of Roman history, and I'm in the process of creation my own Roman-esque campaign. Even though my campaign is built around an earlier version of Rome (I'm aiming for approximately 100 BC, whereas it seems your setting is probably closer to 100 AD) we have many similiar ideas. I would love to hear more about your campaign, and would encourage you to post in Plots&Places.
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Cheers mate!

keep meaning to add all my stuff to my homebrew setting on my site but lol, always doing something else!!
What I can't abide is when folk make another world
exactly like ours, that is without thinking what the differences could cause, etc , if you know what I mean? They sure as heck wouldn't be exactly like our world.
Like in my setting, it's D&D, adamantine exists in D&D and I thought what the heck would that do to it? I imagined legions armed/armoued in adamantine.
It's easy to take things like the ROman slavery that really existed running mines, which were actually amazing feats of engineering, but horrible to work in...take that to D&D. But remember to add the differences!
So I made it where they send condemend criminals to die slowly and horribly. Adamantine is super hard, what would that do to those mining it? I thought well, shred their lungs, ick, jsut as coal dust asbestos etc kills folk in real life but even worse.
The Empire is extremely practical, bar notorious crimes that have to be publicly dealt with (in the arena or by "crucipyre" the empire's notorious method of execution), so why execute a condemend criminal, when you can get him to mine for you for a few years to a profit?
(Romans were often vicious scumbags, but
practical vicious scumbags!

)
The galleys don't use slaves, too high a risk and they are iffy (poor performance) and only the inland ones use oars anyway because galleons and other vessels are used that don't need oars anyway.
The Empire executes the worst criminals by tying them to a metal cross and putting a fire at it's back...the most elaborate ones are hollow pipes in a X fahsion...
the EMpire once upon a time had the god of conquest and fire as it's main deity and that's where that came from. Scares the living heck out of folk.
And you have ot accept the fact that the Romans WERE brutal and not flinch from that, it wasnt "lovely dovey huggy paladin land", hehe.
Over time the Empire in my game has become more "good" for many reasons, but is still ruthless.
In real life the ROmans started moving away form slavery not because of moral grounds, but because it's not good economically (slaves don't buy much, for example, and they don't produce highhest quality as their heart's not in it, so bar some things, freemen work much better). The EMpire in my game is deeply immersed in trade.
On warfare, Barbara Hambly wrote a series about a mercenary general who develops magic abilities by happenstance, so has ot go learn arcane stuff before it kils him, and has cool (but minor) stuff about mercenary units etc.
"Wtiches of Wenshar" was the 1st one?