Life in the colony was perilous, and many died during the Starving Time in 1609 and in a series of conflicts with the Powhatan Confederacy that started in 1610, and flared up again in 1622, when led by Powhatan's brother, Opechancanough. Only 3,400 of the 6,000 early settlers had survived by 1624. However, European demand for tobacco fueled the arrival of more settlers and servants. The headright system tried to solve the labor shortage by providing colonists with land for each indentured servant they transported to Virginia. African workers were first imported to Jamestown in 1619 initially under the rules of indentured servitude. The shift to a system of African slavery in Virginia was propelled by the legal cases of John Punch, who was sentenced to lifetime slavery for attempting to escape servitude in 1640, and of John Casor, who was claimed by Anthony Johnson as his servant for life in 1655. Slavery first appears in Virginia statutes in 1661 and 1662, when a law made it hereditary based on the mother's status.