The Queen of Candelore. The Queen of Candelor Series, #1

Princess Gwyndalin Victoria Alexander, finds herself shipwrecked on a lonely island at the beginning of her voyage to Cornrow, where she is to be wed to King Anthony. She realizes she must survive until she can be rescued. Prince Laurance del Mar is selected by Brightland's Head Druid to Companion the future high queen. When Laurance and the king's messenger travel to Kamlaird to escort the princess to Cornrow, they discover her missing.
However, Laurance knows where the lost princess can be found. And find her he does. King Anthony of Cornrow, seventeen years older than Gwyndalin demands that she convert to Christianity, so he may become the Darkdragon of Brightland, but she pleads with him to retain their Pagan ways. Years later, the queen learns that somewhere her and Laurance's love child still lives. But where?