Recommendations for 1632/Ring of Fire style series?

[Zioneer]

My brother greatly enjoys the 1632 series, and he's looking for books that are similar in style and concept. I figured this would be the best sub-forum to ask, though I can have it moved by mods if it isn't. My brother says he really likes the idea of a modern or near-modern nation going back in time to a medieval or ancient time, and worldbuilding and characterization like the 1632 series does would be preferable. He doesn't have an account here (though he really enjoys some TLs), so he wanted me to ask.

 

[Zioneer]

My brother is also looking into the Belisaurius series, if that helps.

 

[Kaiphranos]

Has he already read the Island in the Sea of Time series? Alternatively, if the late Roman/early Byzantine stuff interests him, he should try Lest Darkness Fall--though that one only features one guy rather than a whole town...

 

[Incognitia]

Safehold is quite 1632-like, and possibly worth a look?

 

[Michael B]

Try H Beam Piper's Lord Kalvan series.