From the time of Cicero--that is, from the time of Julius Caesar, and the establishment of the Empire--the sentiment of brotherhood, the idea of a common humanity, spread with certainty and rapidity, and is reflected in the writings of the philosophers. The exclamation of the Roman poet, "As a man, I regard nothing human as alien to me," which was so heartily applauded by the auditory in the theatre, expressed a growing and almost popular sentiment. The works of Seneca abound in fine humanitarian passages, and it must be remembered that if the Christians were tortured by Nero at Rome, it was by the same hand that Seneca's life was cut short. "Wherever there is a man," said this thinker, "there is an opportunity for a deed of kindness." He believed in the natural equality of all men. Slaves were such through political and social causes, and their masters were bidden to refrain from ill-using them, not only because of the cruelty of such conduct, but because of "the natural law common to all men," and because "he is of the same nature as thyself." Seneca denounced the gladiatorial shows as human butcheries. So mild, tolerant, humane, and equitable was his teaching that the Christians of a later age were anxious to appropriate him. Tertullian calls him "Our Seneca," and the facile scribes of the new faith forged a correspondence between him and their own St. Paul. One of Seneca's passages is a clear and beautiful statement of rational altruism. "Nor can anyone live happily," he says, "who has regard to himself alone, and uses everything for his own interests; thou must live for thy neighbor, if thou wouldest live for thyself." Eighteen hundred years afterwards Auguste Comte sublimated this principle into a motto of his Religion of Humanity--_Vivre pour Autrui_, Live for Others. It is also expressed more didactically by Ingersoll--"The way to be happy is to make others so"--making duty and enjoyment go hand in hand.