People's social circumstances, clothing styles, and the places where they sat naturally brought about their manners of sitting. The development, in the Muromachi period, of Japanese architecture in which the floors were completely covered with tatami (thick straw mats), combined with the strict formalities of the ruling warrior class for which this style of architecture was principally designed, heralded the adoption of the sitting posture known today as seiza as the respectful way to sit. By the middle of the Edo period, it had become a convention for samurai to sit in this manner when meeting authority figures such as the Shogun as a symbol of obedience and loyalty.