A strange woman gives you an ornate box sealed with wax and hoarsely whispers "It's up to you now, keep it safe, keep it from ... them." It is not until the woman drops dead at the character's feet that the dagger in her back becomes obvious.
Approaching adulthood you experience wanderlust and decide to travel, roll 1d6 to detirmine years spent travelling and think about where your character might have gone. (work with your DM to determine details)