The historical figure considered most influential in the development of the Japanese tea ceremony was Sen no Rikyū. Rikyū served as tea master to both daimyos Oda Nobunaga and Toyotomi Hideyoshi. He lived during the upheavals of the Sengoku period, in which political and social structures were radically transformed. Rikyū grew up in Sakai, where the wealthy merchant class was able to establish itself as a cultural and economic force capable of shaping Japanese tea culture. Rikyū, the son of a Sakai fish merchant, studied tea under Takeno Jōō. Like Jōō, he was a proponent of the "wabi" style of tea.