The drum tempo varies between fast and slow, merging with singing voices which at times are elevated in pitch, other times deep and powerful. In brilliant costumes, lissome movements are in every gesture. Actors and actresses are differentiated by distinctive make-up, so that the audience can easily identify between the loyal and the obsequious, the noble ranks and humble subjects. This is hât bôi (classical theatre), a performing art in Âu Lac (Vietnam), originating from and becoming more widespread among them in the 13th century under the Lý and the Trân dynasties. In the later Lê dynasty, classical theatre was introduced to the Court to entertain the royal family and mandarins.