The words of the comic playwright P. Terentius Afer reverberated across the Roman world of the mid-2nd century BCE and beyond. Terence, an African and a former slave, was well placed to preach the message of universalism, of the essential unity of the human race, that had come down in philosophical form from the Greeks, but needed the pragmatic muscles of Rome in order to become a practical reality. The influence of Terence's felicitous phrase on Roman thinking about human rights can hardly be overestimated. Two hundred years later Seneca ended his seminal exposition of the unity of humankind with a clarion-call:

 What author had a great impact in Rome?