Generally I really like books by Rosemary Sutcliff, but this was not my favorite of hers. There was enough plot to keep one's interest, but at times it seemed to move very slowly. (Especially when Walter is imprisoned.)
Pluses to the book are that the main character/story line are atypical; that is, Bess is 'old' even by today's standards when she marries, and that is quite early in the book. At the end, she's an old lady. The following a life's story happens so rarely in books. (Perhaps because we humans are so short-sighted.)
A very sad thing happens at the end, sadder still than the fate of Walter. Ralegh forgets his second son. Usually character mistakes such as this are accounted for by Sutcliff, and this one baffled me.