The Prince and the Pilgrim is one of Mary Stewart's most recent books, published in 1996. It's also one of her weakest, with underdeveloped characters and trite Romance. This has none of the epic sweep of the Merlin books, nor does it have the intimate feeling of The Wicked Day.
The main characters are Alexander the Fatherless, whose father was murdered when he was very young, and Alice the Motherless, whose mother died giving birth to her. Alexander is the cookie-cutter Brave Young Hero of Arthurian myth, while Alice is a shadowy reflection of Lady Stewart's female action-adventure heroines.
Unlike the Merlin books, or A Walk in Wolf Wood the midievil mood is simply not there. It's not a bad book, it's simply not as good as it could have been.