Xena was a young elven servant working with others in the Howe estate while Nathaniel was about the same age as she. Even though they were of different races, they often found time to play when she didn't have chores.
"But it was long before he went to the Free Marches and the tenth Blight started and well, everyone's story has to start somewhere and this is mine." As told to a scholar in Denerim and it was thusly added to the archives as well within the Circle of Magi and told by her family all the way through.