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.
Rebellion: As an adolescent you joined a rebellion against the local ruler, if successful you are outlawed, if it failed you escape, with only friends and family knowing your involvement. (Work with your DM to detirmine the details)
You become involved with criminal elements of society, taking to a life of crime and earning a notorious reputation and bounty. (work with your DM to determine details)