Spanish colonists brought African slaves to Cartagena in the sixteenth century. They were purchased to replace the indigenous peoples who died under the harsh working conditions in the mines and on the plantations. The main slave port for the colony (then Granada) was Cartagena. By 1600 about 100,000 slaves had been brought to the colony. The rate increased after 1650 because of labor needed for the gold mines. Conditions were harsher for some slaves than others. Most were allowed to mine, farm and sell their goods for one day a week. The money they made could buy their freedom. Slave rebellions in the sixteenth and eighteenth centuries had slaves forming their own villages in uncontrolled areas. Slavery was abolished in 1851.