DOUBLE CHURCHES. Before leaving ecclesiastical buildings, it is necessary to allude to a class of double churches and double chapels. Of the former the typical example is the church of Schwartz Rheindorf, erected by Arnold von Wied, Archbishop of Cologne, on his return from Constantinople in 1148, and dedicated in the year 1151. It is in itself a pleasing specimen of the style, irrespective of its peculiarity. It is, however, simply a church in two storeys, and was originally built as a mausoleum, and in the form of a Greek cross without a tower at the intersection. After the death of the Archbishop, his sister Hedwig (Abbess of Essen) extended the nave two bays towards the west in order to form a junction with a nunnery which she had built on the west side. It is probable that the Byzantine plan first carried out exercised much influence on the churches at Cologne and the Rhine generally. At first sight, the lower church looks like an extensive crypt, but this does not seem to have been its purpose so much as to afford an increase of accommodation, to enable two congregations to hear the same service at the same time, there being always in the centre of the floor of the upper church an opening sufficient for those above to hear the service, and for some of them at least to see the altar below. In castle chapels, where this method is most common, the upper storey seems to have been occupied by the noblesse, the lower by their retainers, which makes the arrangement intelligible enough.[69] [Illustration: 718. Section of Church of Schwartz Rheindorf. Scale 50 ft. to 1 in.] The church at Schwartz Rheindorf is not large, being only 112 ft. long, over all, by 53 ft. wide across the transepts; and the two western bays appear to have been added afterwards. The walls of the lower storey are built of sufficient thickness to admit of a gallery being carried all round the church externally on the level of the floor of the upper church. This gives it a very peculiar but pleasing character; and as the details are good and appropriately designed, it is altogether as characteristic and as original a design as can well be found of the purely German style of its age. [Illustration: 719. View of the Church of Schwartz Rheindorf. (From Simon.)]