To the archæologist the Round Churches form the most interesting group in the Scandinavian province, though to the architect they can hardly be deemed of much importance. They are, however, so remarkable that many theories have been formed to account for their peculiarities. The most general opinion seems to be that the circular form was adopted for defensive purposes; and this seems to be borne out by the description given in Major Heales’ work, who, referring to the four examples in Bornholm (which are of the same type as others in the Scandinavian provinces), states, pp. 26 and 29: “Each consists of a circular nave, a chancel, and an apse.” The dimensions are always moderate; the internal diameter of the naves being, Olska, 34 ft. 2 ins., Nyska, 35 ft. 4 ins., Nylarska, 38 ft. 2 ins., and Oester Larsker, 42 ft. 3 ins. (Woodcut No. 793) “In two cases even the chancel wall are convex in plan, so that their ground plan is formed without a single straight line.” The nave is covered with a vault carried on a central pier (except in the case of the Oester Larsker, where there are six piers, the space in the centre being open to an upper storey). The second storey is similarly vaulted, and the central pier rises to carry the roof timbers of the third or upper storey. “The walls of the nave vary in thickness from 5 to 6 ft.”— “beyond a small doorway and a few loopholes measurable by inches there are no external openings except in the upper storey, which consists of a gallery formed in the thickness of the wall and lighted by loopholes arranged not to correspond with the openings by which the gallery is entered from the central chamber.” The approach to this upper chamber as well as to that of the first floor is by narrow, steep, and crooked staircases in the thickness of the wall, which could be easily defended, at all events for a time, the assumption being that the church might be attacked by freebooters coming by sea whose onslaught would not be of long duration. [Illustration: 792. Section and Ground-plan of Round Church, Thorsager. (From Marryat’s ‘Jutland and the Danish Isles.’)] The circular form of church would seem to have been much more common in Northern Europe in the early centuries of the Christian faith than afterwards. In the richer and more populous South they were superseded, as has above been pointed out, by basilicas of more extended dimensions, into which they were frequently absorbed. In the poorer North they have sufficed for the scant population and remained unchanged. [Illustration: 793. Round Church of Oester Larsker, Bornholm. (From Marryat’s ‘Jutland and the Danish Isles.’)] Mr. Marryat enumerates eight examples in Denmark,[94] and there are at least as many, if not more, in Sweden. All are of Teutonic type—naves with small apses—as contradistinguished from the French or Celtic form, where the circular part became the choir to which the nave was added afterwards.