(_a_) We must wholly distinguish from Gothic architecture, such as I have above described it, the so-called pre-Gothic, whose development originated in Roman architecture. The most ancient form of Christian churches is that of the _basilica._ These originated out of the public buildings of the Empire, huge oblong halls, with the frame-work of their roofing of wood, such as Constantine placed at the disposal of Christians. In buildings such as these there was a tribune, on which, during congregational religious services conducted by priests, there was singing and an address delivered, or merely reading aloud. The conception of the choir may have originated with this. In the same way Christian architecture accepted other of its forms such as the use of columns with circular arches, the rotunda and the modes of classical embellishment throughout, more particularly in the western Roman Empire, while in the eastern section it appears to have remained constant to this type until the time of Justinian. Even buildings erected by the Ostrogoths and Lombards in Italy retained essentially the fundamental Roman type. In the more recent architecture, however, of the Byzantine Empire several modifications made their appearance. A rotunda supported on four great piers forms the centre, to which different constructions were attached to meet the particular objects of Greek as distinct from the Roman ritual. We must not, however, confuse this genuine architecture of the Byzantine Empire with that which, in its general relation to architectural types, goes by the name of Byzantine, and which was employed in Italy, France, England, Germany, and other places up to the close of the twelfth century. (_b_) In the thirteenth century was evolved the Gothic architecture in the distinctive form whose main characteristics I have above described in detail. It is nowadays denied that it is the work of Gothic architects, and the name given it is that of Deutsch or German architecture. We may, however, retain the more customary and ancient nomenclature. In other words we find in Spain very ancient indications of this type of construction, which suggest an association with historical circumstances under which Gothic kings, forced back into the mountains of Asturia and Galicia, retained their independence in such localities. Under such conditions, no doubt, a close affiliation of Gothic and _Arab_ architecture appears probable, yet both may be essentially distinguished. For the characteristic trait of Arab architecture in the Middle Ages is not the pointed arch, but the so-called _horseshoe_ form. Moreover, these buildings, which are constructed for an entirely different ritual, exhibit an Oriental wealth and splendour, embellishments resembling plant-life and other forms of decoration, which, in an external form, mix together what is of Roman ancestry and that which belongs to the Middle Ages.