development generally was William Berkeley, who served, with some interruptions, as governor of Virginia from 1645 until 1675. His desire for an elite immigration to Virginia led to the "Second Sons" policy, in which younger sons of English aristocrats were recruited to emigrate to Virginia. Berkeley also emphasized the headright system, the offering of large tracts of land to those arriving in the colony. This early immigration by an elite contributed to the development of an aristocratic political and social structure in the South. English colonists, especially young indentured servants, continued to arrive along the southern Atlantic coast. Virginia became a prosperous English colony. The area now known as Georgia was also settled. Its beginnings under James Oglethorpe were as a resettlement colony for imprisoned debtors. Rise of tobacco culture and slavery in the colonial South From the introduction of tobacco in 1613, its cultivation began to form the basis of the early Southern economy. Cotton did not become a mainstay until much later, after technological developments, especially the Whitney cotton gin of 1794, greatly increased the profitability of cotton cultivation. Until that point, most cotton was farmed in large plantations in the Province of Carolina, and tobacco, which could be grown profitably in farms of smaller scale, was the dominant cash crop export of the South and the Middle Colonies. In 1640, the Virginia General Court recorded the earliest documentation of lifetime slavery when it sentenced John Punch to lifetime servitude under his master Hugh Gwyn for running away. During this period, life expectancy was often low, and indentured servants came from overpopulated European areas. With the lower price of servants compared to slaves, and the high mortality of the servants, planters often found it much more economical to use servants. Because of this, slavery in the early colonial period differed greatly in the American colonies from that in the Caribbean. Often Caribbean slaves were worked literally to death on large sugar and rice plantations, while the American slave population had a higher life expectancy and was maintained through natural reproduction. This natural reproduction was important for the continuation of slavery after the prohibition on slave importation after about 1780. Much of the slave trade was conducted as part of the "triangular trade", a three-way exchange of slaves, rum, and sugar. Northern shippers purchased slaves using rum, made in New England from cane sugar, which was in turn grown