I don't remember where I saw a rec for this book (somewhere on DW, probably) but I finished it today and absolutely loved it. You know how sometimes you read a book and just want to start reading at the beginning immediately? This was one of those books.

Island of Ghosts is set in Britain towards the end of Roman rule. A detachment of Sarmatian cavalry -- effectively hostages from a conquered steppe tribe, considered dead by their own relatives -- arrive to reinforce the defenses at Hadrian's Wall. The Sarmatians are baffled by the settled farming people around them, struggling to cope with the idea of living in houses rather than wagons, chafing under Roman laws and trying to learn a foreign language; meanwhile the local Britons (who have only recently and very tenuously become Roman themselves) consider them incomprehensibly barbaric, these horse-riding people who wear coats made of their enemy's scalps and solve their differences through duels to the death, while the Roman provincial rulers and cavalry commanders can't see why everyone can't just peacefully assimilate and be part of the empire already.

I couldn't say how true to historical fact the broad strokes of the characters' attitudes and cultural details are, though the specific events of the book are obviously fictional. However, the general tone of the book is a lot less dark and grim than historical fiction frequently is, which I noticed a few reviewers on Amazon taking it to task for, along with the fact that it's tropey as hell (which for me is a feature, not a bug). I don't want to give the impression that dark stuff doesn't happen -- this is a book that includes a description of a pregnant woman having her baby cut out of her womb and being thrown onto a bonfire along with her infant and toddler. The protagonist's people have a practice of decapitating their enemies and turning their skulls into drinking cups, while the Britons practice human sacrifice and the Romans are, well, the Romans. I really appreciated, in fact, that the protagonist is not magically innocent of this kind of thing. He's the leader of a group of soldiers who have been fighting a brutal war against the Romans. Nobody's hands are clean. Similarly, the Romans are not portrayed as a shining light of civilization but are shown to be just as barbaric and cruel in their own ways as the so-called "barbarians", particularly in their treatment of slaves, women, and religious minorities. (Other potentially offputting material that might be DNW for some readers includes an infant being exposed to die and a subplot involving abuse of carriage horses, as well as animal fights as entertainment. There's no on-page rape or rape as a backstory for any of the protagonists, but it's suggested that there was quite a lot of it during the war.)

But on the whole, this is a book that's about picking up the pieces. It's about people looking beyond their differences and learning to lay aside old hurts in the aftermath of a war, putting themselves back together and making each other better. This book mashed down all my buttons for making friends with your enemies, found families, getting back up after you get kicked down, and soldiering on (literally) in the face of loss and pain. I adored the characters, and there's a side romance I really enjoyed, but there's also a strong focus on friendships, parents and children, and community as relationships of equal importance. It's a book about being torn away from your home and family, and then finding a new one.

I haven't read anything by this author before, or even heard of her, but I'm definitely going to be looking up her other books. (Looks like she has one that's about werewolves in the Crusades. I AM THERE.)

ETA: One thing I should mention is that the Kindle edition contains a lot of OCR errors, including a recurring problem getting the protagonist's name right. It's also fairly expensive. I don't regret having paid for it because I loved it Just That Much, but the print version is probably more readable; I assume it doesn't have the same issue.