II granted the land to eight Lords Proprietors in return for their financial and political assistance in restoring him to the throne in 1660. Anthony Ashley Cooper, one of the Lord Proprietors, planned the Grand Model for the Province of Carolina and wrote the Fundamental Constitutions of Carolina, which laid the basis for the future colony. His utopia was inspired by John Locke, an English philosopher and physician, widely regarded as one of the most influential of Enlightenment thinkers and commonly known as the "Father of Liberalism". The Carolina slave trade, which included both trading and direct raids by colonists, was the largest among the British colonies in North America. Between 1670 and 1715, between 24,000 and 51,000 captive Native Americans were exported from South Carolina – more than the number of Africans imported to the colonies of the future United States during the same period. Additional enslaved Native Americans were exported from South Carolina to other U.S. colonies. The historian Alan Gallay says, "the trade in Indian slaves was at the center of the English empire's development in the American South. The trade in Indian slaves was the most important factor affecting the South in the period 1670 to 1715". In the 1670s, English planters from Barbados established themselves near what is now Charleston. Settlers from all over Europe built rice plantations in the South Carolina Lowcountry, east of the Atlantic Seaboard fall line. Plantation labor was done by African slaves who formed the majority of the population by 1720. Another cash crop was the indigo plant, a plant source of blue dye, developed by Eliza Lucas. Meanwhile, Upstate South Carolina, west of the Fall Line, was settled by small farmers and traders, who displaced Native American tribes westward. Colonists overthrew the proprietors' rule, seeking more direct representation. In 1712, the former Province of Carolina split in to North and South Carolina. In 1719, South Carolina was officially made a royal colony. South Carolina prospered from the fertility of the lowcountry and the harbors, such as at Charleston. It allowed religious toleration, encouraging settlement, and trade in deerskin, lumber, and beef thrived. Rice cultivation was developed on a large scale on the back of slave labor. By the second half of the 1700s, South Carolina was one of the richest of the Thirteen Colonies. The American Revolution On March 26, 1776, the colony adopted the Constitution of South Carolina,