Constantine, in the mighty ardour of his zeal, wished to see the worship of the true God efface in pomp and in magnificence all the solemnities of the heathen world. In expelling the idols from their temples, the idea could not have suggested itself of using these buildings for the new religion, because they were generally of excessively limited dimensions, and the plan on which they were built would have but indifferently answered the requirements of the Christian ceremonial. What was necessary for these services was principally a spacious nave, in which a large congregation could assemble to hear the same word, to join in the same prayer, and to intone the same chants. The Christians sought, therefore, among the edifices then in existence (Fig. 295), for such as would best answer these purposes. The _basilicas_ presented themselves; these buildings served at once as law-courts and places of assembly for tradesmen and money-changers, and were generally composed of one immense hall, with lateral galleries and tribunes adjoining it. The name of _basilica_, derived from the Greek word _basileus_ (a king), was given them, according to some writers, from the fact that formerly the kings themselves used to administer justice within their walls; according to others, because the basilica of Athens served as a tribunal of the second archon, who bore the title of king; whence the edifice was called _stoa basiliké_ (royal porch), a designation of which the Romans preserved only the adjective, the substantive being understood. [Illustration: Fig. 295.--Basilica of Constantine, at Trèves, transformed into a Fortress in the Middle Ages.] “The Christian basilica,” says M. Vaudoyer, in his learned treatise on architecture in France, “was most certainly an imitation of the heathen basilica; but it is of importance to observe that from one cause or another the Christians, in the construction of their basilicas, very soon substituted for the Grecian architecture of the ancient basilicas a system of arches reposing directly on isolated columns, which served as their supports; a perfectly new contrivance, of which there existed no previous example. This new mode of construction, which has generally been attributed to the want of skill in the builders of this period, or to the nature of the materials they had at their disposal, was, however, to become the fundamental principle of Christian art; a principle characterised by the breaking up of the range of arches, and by the abandonment of the system of rectilinear construction of the Greeks and Romans.