In the century after the collapse of the Romano-British economy, very few substantial buildings were constructed and many villas and towns were abandoned. New long- and round-houses were constructed in some settlements, while in others timber buildings were built imitating the older Roman styles. The Germanic immigrants constructed small rectangular buildings from wood, and occasionally grander halls. However, the conversion to Christianity in the 6th and 7th centuries reintroduced Italian and French masons, and these craftsmen built stone churches, low in height, following a narrow, rectangular plan, plastered inside and fitted with glass and colourful vestments. This Romanesque style developed throughout the period, featuring characteristic circular arches. By the 10th and 11th centuries, much larger churches and monastery buildings were being built, featuring square and circular towers after the contemporary European fashion. The palaces constructed for the nobility centred on great timber halls, while manor houses began to appear in rural areas.