(_a._) As the concrete embodiments of man’s thoughts; the importance of the historical study of which cannot be too strongly insisted upon, for through it we can best become acquainted with the past, from a social and religious point of view. (_b._) As products that act upon our emotional, intellectual, and reasoning faculties. It is our duty to endeavour to ascertain what forms at different times, and under various impressions, acted most agreeably on us. We must learn to know the causes that produced certain art forms at certain periods, amongst certain people, under certain intellectual, social, and religious conditions. We must inquire why such forms flourished, decayed, or revived at different times. (_c._) We may examine the relations in which our subjective impressions stand to the products of art, and learn how far such sensations developed, in time and space, to lead us to the consciousness of beauty. From pre-historic times to the advent of Christ humanity was always engaged as a busy artist. In studying the history of man we find that art ushers us into life, gladdens the child, inspires the youth, and interests the man. All our public actions, all our religious ceremonies, our Court pageantry, our battles and funerals, all our useful or useless surroundings, pass more or less through an artistic process. In analysing the historical development of humanity at large, or that of a nation, or even that of single individuals, we find that our sensations, intellect, and reason have always been at work to create something in their respective spheres. From the times of Plato to our own all great thinkers have more or less occupied themselves with the endeavour to establish the principles of beauty; just as from Thales of Miletus, and Demokritos to Bacon, Kant, Darwin, and Häckel, they have sought to discover the principle of truth; or from Manû, Confucius, Moses, the Apostles, and Mahomet, to our own theologians, they have striven to decide what is right or wrong. Art worked synchronically with these endeavours, and its products are as numerous and variegated as our philosophical systems, or our creeds and sects. Moreover, works of art are, in many instances, far less perishable than works of mere speculation. It becomes an imperative duty, therefore, to study historically one of the most important branches of human activity and ingenuity, which furnishes us in its very products with a record in lasting forms, with at least the same ardour, earnestness, and veneration, with which we devote ourselves to more varying, changing, and perishable products. One fact must be obvious to every reader of these pages--that real art has so exalted a sphere that it can only exist to perfection wherever sciences and morals are highly cultivated.