The Lantern Bearers by Rosemary Sutcliff
Recommended Reading Age: 13
This is the third and last book in the "trilogy*" that consists of The Eagle of the Ninth, The Silver Branch and this book, The Lantern Bearers. I thought that this book was very bitter-sweet.
It starts on a rather happy note: the main character is Aquila, a Roman soldier on leave at the family farm. About a chapter into this book, however, things begin to change, when Aquila is called back to the fort. After a disastrous episode, he is taken captive by a band of raiding Saxons. The rest of the book is all about his escape and subsequent joining of a British war band.
I really enjoyed how this book showed him as he really grew up, from being a bitter and angry young man to being a more mature person in his mid-thirties. There are many parts that really touched my heart.
*This, along with the three books being a chronological series, has been published as one volume called The Three Legions.