The plastic art, which is the art of modelling in the round with a pliable material, was with little doubt the earliest development of the imitative arts. To an untrained mind it is a more obvious method, of copying or delineating an object, than by lines on a flat surface. Its origin is so early and so involved in myths and legends, that any attempt to ascribe its invention, to a particular nation or to a particular individual, is impossible. Its earliest form was doubtless monumental. Frequent passages in the Scriptures show this, and that the Hebrews practised it, as did also their neighbors the Phœnicians; while excavations have revealed the early plastic monuments of the Assyrians. For more than two thousand years the Egyptians are known to have associated the plastic arts with their religious worship, but, being bound within priestly rules, made no perceptible progress from its beginning; yet these crude monuments of ancient Egypt are now the records of the world’s history of their time. Associated with architecture from its earliest development, it has, in its narrower form of sculpture, been called, not inaptly, “the daughter of architecture.” Indeed, in the remains of ancient monuments, the two arts are so intimately combined, that architecture is frequently subordinated to sculpture, particularly in the buildings of the middle ages, where they appear as very twin sisters, sculpture often supplying structural parts of the erection. Among the Greeks the plastic art existed from time immemorial, and among them attained its highest proficiency and skill. That they exceeded all others in this art goes without saying; their familiarity with the human form enabling them to portray corporal beauty with a delicacy and perfection, that no society, reared in any other situation or surrounded by other influences, could ever attain. With them beauty was the chief aim, it having in their eyes so great a value that everything was subservient to it. As has been said, “It was above law, morality, modesty, and justice.” Greek art, as we know it, began about 600 B.C.; but it did not arrive at its perfection until the time of Pericles, a century and a half later, in the person of Pheidias, who consummately illustrates its most striking characteristics--the simplicity with which great efforts are attained, and the perfect harmony which obtains between the desire and the conception, the realization and the execution. The frieze of the Parthenon, which easily holds the supreme place among known works of sculpture, is ample proof of this.