During the Nara period (Japan 710-794) tea plants were grown in Japan and mainly consumed by priests and noblemen as medicine. Toward the end of the Tang dynasty in China, the drinking of tea was going through a transformation from medicine to beverage, but due to deteriorating relations between the two countries this transformation did not reach Japan till much later. The Japanese were forced to mold and cultivate their own traditions and culture around the tea. Tea was a rare and valuable commodity from the Nara period to the Heian period (794-1192) so rules and formalities were based on this concept. Had tea been native to Japan or more readily available, it is almost certain that the tea ceremony would not have been created.