Until the 1970s, few professional Japanese historians regarded material culture and lifestyles as subjects of serious inquiry. The civil wars of the sixteenth century and the concurrent social and economic developments were catalysts in the transformation of the material culture and lifestyles of the common folk. During the Tokugawa period, patterns of income distribution in city and countryside alike changed as a result of economic growth, led by continued growth in the agricultural sector and the accelerated growth of commerce. Premodern Japanese buildings were built of tensile materials such as wood, bamboo, and thatch. The new foods introduced during the late medieval period, rises in agricultural productivity during the Tokugawa period. The Tokugawa period saw a distinct rise in the quality of life, owing to the introduction of a new fiber for cloth. The rising standard of living both brought the Japanese more goods and some luxuries and also improved the quality of their life.