He refused to sign the Constitution because it lacked a Bill of Rights; he urged it to abolish slavery. He wrote the Bill of Rights in the Virginia constitution, and this was the eventual template for what would become the US Constitution's first ten ammendments. These were radical, novel ideas: codified individual "inalienable" rights that the state could not breech; a ban on slavery. No nation on earth at that time, or before, instituted such concepts. Not the Azteks, the Myans, the Etheopians, the Egyptians, the Romans, the Greeks, pan-islamia, the Persians, the Zulus, nobody.