You were Uhtreds eldest daughter, hidden and raised amongst Danes. It was for your own safety , as Uhtred was sought out by many men that wanted him dead, and he did not want you to be at risk or used as a leverage against him. Ragnar, his brother by heart and not blood, legitimate son of Ragnar The Fearless took you in and trained you to be the warrior woman you are today. You were dangerous, better than any swordsman and warrior Ragnar has ever had by his side.