[Illustration: Fig. 4. St Peter's, Barton-on-Humber: from S.W.]
§ 21. In these buildings we seem to discover the influence of the centralised plan, acting through the channel of German art. It would be absurd to say that the plan of Barton-on-Humber was inspired by the plan of the palace-church at Aachen, which was an adaptation, with some improvement, of the plan of San Vitale at Ravenna. No masterly intellectual effort, such as the Aachen plan shows, was necessary to plan a rectangle with two smaller rectangles at either end. But the church at Aachen had made the centralised plan familiar to the builders of western Europe. In Germany and in France there are traces of its influence; and we may reasonably suppose that the builders of Barton-on-Humber were acquainted with the existence of an alternative to the usual plan of the church with a longitudinal axis, and did not arrive by haphazard at their concentration of the plan upon a central point. One earlier example of the centralised plan is known to have existed in England. In addition to his basilica at Hexham, Wilfrid had built another church there in the shape of a Greek cross. The description of it which we possess shows that the central space was the actual church, that it was tower-like in form, and nearly circular in shape, and that the arms were simply porch-like projections. Probably it was a combination of baptistery with tomb-church. It is not likely that the simple plan of Barton was derived from that at Hexham. Both were probably the result of continental influence; but, while the church at Hexham may have been the work of Gallo-Roman masons in direct communication with the general current of architectural progress, the church at Barton was probably built by Englishmen, who adapted the centralised plan to methods natural to their comparative want of skill.
§ 22. Neither at this time nor later did the centralised plan in England develop along the lines suggested by Barton-on-Humber. No real development on such lines was possible. In Germany, the achievement at Aachen made possible the polygonal nave of St Gereon at Cologne and the centralised plan of the Liebfrauenkirche at Trier, as well as many twelfth and thirteenth century churches whose complicated parts are planned and massed together with relation to a central tower space. In England, however, the habit of dealing with circular or polygonal forms made little progress; and our few "round churches," the plan of the naves of which was a devout imitation of the church of the Holy Sepulchre at Jerusalem, and our polygonal chapter houses, are almost all that we have to show in the way of attempts at a definitely centralised plan. Our church plan develops as the result of an effort to combine a series of rectangles effectively; and, while this combination can be attempted in several different ways, it is obvious that the rigid lines of the rectangle do not admit of that free scope in centralised planning which is given by the circle or polygon.