It's a work of historical fiction that is about a fictional spartan soldier's account of the battle of Thermopylae. I understand that most of the character and sub plots are made up, but how well does the book portray Spartan culture, and the actual battle itself.
I need to rush off, so,I can't give a long answer. I need to find my copy and skim through it so I can see about how accurate details were, but I found this review, saying it is not very historically accurate. Imo, it is, largely, historically accurate, and compared to other historical fiction books, the accuracy is great, but there are small details which are apparently wrong. Frankly, I think the reviewer is too nit picky, apart from his noting about how the consequence of injury is often overlooked (seeing how much the fear of gangrene, lockjaw etc would be prevalent), but the other inaccuracies he notes are for very small things, like the metals used in the tips of spears. It captures the feelings and emotions behind Spartan warriors well, I think it is accurate at capturing the mood and atmosphere at the time- and very minor details can therefore be overlooked. Ignoring stuff like gangrene and lockjaw isn't as minor, but ultimately isn't too big a deal. So for portraying the battle and Spartan culture, I would say it is largely accurate. Although I don't actually like the book!