Light Perpetual by Andrzej Sapkowski

This last book of Sapkowski's Hussite Trilogy, sees our hero, Reynevan, journeying across war torn Bohemia and Silesia in search of his true love Jutta of Apolda, who's been abducted and effectively imprisoned in a nunnery. It seems like a journey of 'one step forward, and two steps back', as Reynevan is sent in first one direction then another, following information about where Jutta might be being held, trying to avoid his enemies, being sent on missions which take him in the wrong direction, and ending up captured himself. Through it all though he holds true to his purpose, ever striving for news of Jutta,

Sapkowski is better known as the author of fantasy novels - The Witcher series - rather than historical,  and, although the Hussite trilogy is set firmly in central Europe during the wars of the early 15th century, there's more than a touch of fantasy about it; Reynevan uses magic in his work as a physician, or amulets to help him pass unnoticed; his arch-enemy, Grellenort, shape-changes between man and bird. So it should appeal to fans of both genres. Be warned, this isn't historical romance but a story set during times of war, and aiming for a level of realism, meaning there's a lot of violence and casual brutality. 

I've come to the series late, starting with the last book, but that didn't detract from my enjoyment, although some aspects are not totally clear at the beginning, and there seemed to be a plethora of characters - good and bad - to become acquainted with in the first few chapters. At over 600 pages, it's long - normal for fantasy novels, less so for historical (unless you're thinking of Wolf Hall) - but settle in for a long consuming read and you won't be disappointed.