Slaves didn't get actual rights until the Roman Empire was in full rise. For instance Claudius declared that if a slave is abandoned by his master, he is free, and Nero announced that slaves have he right to complain about their masters in court, and under Antoninus Pius, a master who killed his slave without a legitimate reason. By mid to late 2nd century AD, it became common for slaves to complain of cruel and unfair treatment from their masters. Before the privileged rights to slaves were obtained, slaves were able to buy their freedom, be set free by their masters, and some gladiators were won their freedom.