The other ancient text, "Naradiyasiksa" dated to be from the 1st century BC, discusses secular and religious music, compares the respective musical notes. This is earliest known text that reverentially names each musical note to be a deity, describing it in terms of "varna" (colors) and other motifs such as parts of fingers, an approach that is conceptually similar to the 12th century Guidonian hand in European music. The study that mathematically arranges rhythms and modes ("rāga") has been called "prastāra" (matrix).