Ca Trù - an original art performance of academic character - has been preserved for the past 10 centuries.To appreciate Ca Trù is to appreciate poetry and music. Ca Trù appeared officially under Nhà Hậu Lý (11th century). First, it served royal and religious rituals and was called Hát Khuôn. Later, it was used in banquets, weddings, friendly meetings... and called Hát Hàng Hoạ Ca Trù had bamboo castanets as principal+instrument. By beating time on tomtoms, spectators accompanied and praised the singer. Ca Trù was also called Hát Nhà Trò (singing or dancing while pulling funny tricks), Hát Thưởng (Singing to be rewarded by king or mandarins), Hát Cửa Quyền (singing in royal palaces), Hát Cửa Đình (singing for religious rituals), Hát ả đào (name of a famous songstress in the Lý times).... Under the French domination, Ca Trù declined. Nowadays, it is restored as a type of original popular art