From the Wikipedia article 
Sen no Rikyū (千利休?, 1522 - April 21, 1591, also known simply as Sen Rikyū), is considered the historical figure with the most profound influence on chanoyu, the Japanese "Way of Tea", particularly the tradition of wabi-cha. He was also the first to emphasize several key aspects of the ceremony, including rustic simplicity, directness of approach and honesty of self. Originating from the Edo Period and the Muromachi Period, these aspects of the tea ceremony persist. Rikyū is known by many names; for convenience this article will refer to him as Rikyū throughout.
There are three iemoto (sōke), or "head houses" of the Japanese Way of Tea, that are directly descended from Rikyū: the Omotesenke, Urasenke, and Mushakōjisenke, all three of which are dedicated to passing forward the teachings of their mutual family founder, Rikyū.