Before the Civil War, slavery was a crucial part of the socio-economic system of the southern United States. It was far different from, and worse than, Graeco-Roman forms of slavery because it was so completely grounded in race. Slaves were bought in Africa and distinguished from their owners by ethnicity;many of the laws which segregated and distinguished slaves from masters were framed in terms of skin colour. Thus the situation in Roman, where grandsons of freed slaves were full Roman citizens, with complete equality, and indistinguishable from other citizens, could not happen. In the South, the slaves were chattels, defined as property, subject to being bought and sold, and laboured for their masters in the same way as oxen or horses, and were often treated no better than animals.