Enchant The Dream by Kathleen Morgan

She is Gaelle, the chaste Germani priestess forced in the aftermath of revolt to become a slave to the wealthy and cruel Secundus. He is Cerdic, the Celtic chieftain bound in defeat to surrender his lands and freedom to a Roman barbarian. When their masters' brutality changes their lives forever, Gaelle and Cerdic flee Rome on a journey that will change their lives. Original.