But the ancient times were as essential to the building up of the modern as the modern to the completion of the ancient. It was the renewed study of the Greek classics, of Roman law, and of the original teachings of Christianity, under more favorable circumstances, and after many new experiences for a thousand years, that gave birth to all our later improvements in religion, in government and in science. The Asiatic Jews gave us in Christianity, a pure and simple worship, and a system of public morality so perfect that no society has yet been able to embody it completely in practice, although it is now recognized, very generally, as the highest conceivable standard, to be constantly aimed at and conformed to as far as possible; the Greek Philosopher, Aristotle, gave us the first notions of science, and Roman law formed the base of modern legal practice. 6. The difficulties of progress are very great. It is not easier for nations to unlearn what they have learned amiss in their youth, than for individuals. No nation that has matured institutions has ever yet thoroughly reformed them. The best and most clear sighted minds discover their defects and show what is to be remedied; but the force of habit and the veneration men feel for what is old, offer so much resistance to complete reforms that it has been necessary to establish and build up institutions on new principles on fresh ground. So all the light and power of science, of the reformed religion, of a more complete system of law, the greater intelligence of the masses of men and the activity of commerce and trade did not suffice to do for modern Europe what has been done with ease in America. But Europe furnished the ideas which America worked out; and the sight of those principles embodied in institutions that greatly improved the condition of mankind has reacted on Europe, and bids fair, in time, to produce a novelty in human experience—a complete regeneration of old nations and governments. When Greece rose to power it subjected but lightly, and only superficially transformed, the nations of Asia; Rome absorbed them both, and Christianity gave its simple and noble lessons to them all. But the slight influence of Greece, Rome and Christianity on the old nations of western Asia is shown in the rise and permanence of Mohammedanism, so inferior, in all respects, to Christianity. After a career of more than twelve hundred years, it still rules many more millions than were contained in all the Roman Empire in its most prosperous days.