This is the style of which we should first treat when attempting to trace the history of Mediæval architecture. It is a mistake to imagine Pointed architecture to be severed by a great gulf from the Romanesque--the Pointed Gothic from the Round: it is its legitimate offspring, or rather _itself_ in a more advanced stage of its development. The change from the round-arched to the pointed-arched Gothic is no change of essential principles; it is but the carrying on to their inevitable results of the principles of refinement, purification, elevation, the perfecting of the construction, and the softening down of the asperity of expression, which were going on during the whole of the Romanesque period. Nearly every characteristic of Pointed architecture finds its type, or its perfected model, in the Romanesque. They are not _two_ styles, but _one_--the earlier and the later phases of the _same_ architecture; the latter being only the carrying on to perfection of the progression which had, during every moment of its dominion, and in every province of its empire, been uniformly going on in the former. Though the refining process went unceasingly on during the whole history of Romanesque architecture and affected all its features, it would appear that the constant endeavours to bring to perfection its various systems of _vaulting_ were among the greatest causes of the change from the Round to the Pointed style, I will, therefore, endeavour to give a concise outline of the changes in this branch of construction during the period under consideration. The churches of Western Europe up to this time, like the early basilicas, were for the most part covered with timber roofs; and the task which the Romanesque builders proposed to themselves was to convert them into _vaulted_ churches. The most normal and readily invented vault is that of the continuous barrel or demi-cylindrical form, covering an oblong building from end to end, and the most readily conceived idea, where the building has to be roofed over such a vault, is to fill in the space between the arch and the triangle of the roof solid, and make it at once the ceiling of the room and the support of the roof covering. Such a vault, however, has considerable outward thrust, and, being heavily loaded at the crown, would require walls of great thickness to stand against it. Let us suppose it applied to the nave of a basilica in place of the timber roof, and it is obvious that, being balanced on two ranges of columns, it could not stand for a moment without some very effective contrivance in the construction of the aisles to buttress up the walls and pillars on which this barrel vault is to rest. [Illustration: Fig. 1.]