Edith Pargeter was an excellent writer; sadly, she died recently. She is best known for her "Brother Cadfael" mysteries. Brother Cadfael is a 12th century Benedictine monk who also does a little detective work on the side.
This book is medieval historical fiction at its best. It is actually 4 books in one, 821 pgs. long. Instead of having to hunt them down individually, they've been put together in one huge volume. This is a marvelous story of Llewelyn ap Griffith or "Llewelyn the last." He was virtually the only man in Welsh history who ever got allegiance from all the providences & princes of Wales & believed strongly in an independent Welsh nation. It's also the story of his relationship with his 3 brothers (He being the 3rd & not the traditional heir.), especially his younger brother, David (Davydd) who sometimes loved & supported him & sometimes turned rival & traitor. So it is truly the story of the "brothers Gwynedd" along with some wonderful love stories among them & the other characters.
If you enjoy Welsh history read this book! It is very well written & documents not only the story of the brothers & Wales, but also the history of the relationship between Wales & its larger neighbor England. Here is the long struggle of Wales to try to become an independent nation & its relationship with Henry III & Edward I. Wonderful book! I can't say enough to encourage you to read it.