You are mistaken for the missing offspring of the ruler of the land and are taken to live in the ruler's household. After 1d6 years something happens that causes you to leave. (work with your DM to determine details).
Pickpocket: During your adolescence your family fell on hard times forcing you to turn to petty theft and other criminal activities involving you with criminal organisations.
During your early adulthood you saved someone's life. This person becomes your companion. (work with your DM to determine details) Roll 1d10 on a 9-10 your companion falls in love with you.