Wherein the I Do Not Know What is Happening

I'm attempting to read The Janissary Tree and it's largely incomprehensible to me--like, I'm not sure what's happening ever. In part, that's because my brain shuts down whenever I'm faced with geographical or historical details, or anything involving the military. I tend to quickly go into skim mode and lose the thread of the story or the significance of the pause in action.

A sentence like "Along the rolling hills, just west of the banks of the Tigris-Euphrates, the General Zwick of the Napoleonic army commanded 500 men to hoist their bayonets above their heads and engage in one of the most strategic battles in the Crimean War" has me folding down the corner of the page and possibly throwing the book across the room. I tried very hard last night to keep focused on the action and the asides, but the best I can tell you is that the book is about a(n?) eunuch trying to solve a few murders that have occurred near a sultan. Said murders may or may not be the work of a fringe political group, the Janissaries, who have named themselves after a type of tree that means something significant.

Perhaps I'm frustrated because I know that I won't be able to guess the murderer or motive since I can't follow the story line or identify the main players except for the eunuch. I'm sticking with it because I don't have anything else to read at the moment and because it was an Edgar Award winner, but for the record, I'm not enjoying it very much.