As early as Roman times stoves made of clay, tile, or earthenware were in use in central and N Europe. Early Swiss stoves of clay or brick, without chimneys, were built against the outer house wall, with an opening to the outside through which they were fueled and through which the smoke could escape. Scarcity of fuel made an economical heat-retaining device necessary, and these primitive stoves, built of clay, brick, tile, or plastered masonry, became common in the Scandinavian countries, Holland, Germany, and N France. Some exquisitely colored and glazed tile stoves, dating from the 16th and 17th cent., show traces of Moorish influence. In Russia large brick stoves formed a partition between two rooms. Because of the very long flue, which wound back and forth inside the structure, these could be heated for some hours with a small amount of light fuel.