When did nou originate?

Nou theater is expressed through music and dance.
Nou is based on the song and dance taken from sangaku.
Sangaku was a form of entertainment introduced from the continent during the Nara period and included acrobatics, magic, and song and dance.
This song and ｄance developed in a uniquely Japanese way, and by the latter half of the Kaｍakura period, the stylistic features of the nou theater were completed.
In 1374 the shogun, Ashikaga Yoshimitsu, watched a nou performance and was deeply impressed; after this, the nou theater advanced under his patronage.
Kan'ami and his son Zeami developed the artistry of the nou theatrical form and established its theoretical underpinnings.
Today, there are five schools of nou theater: the Kanze, Hosho, Komparu, Kongo, and Kita.