Indian classical music's origins can be found in the Vedas, which are the oldest scriptures in the Hindu tradition. Indian classical music has also been significantly influenced by, or syncretised with, Indian folk music and Persian music. The Samaveda, one of the four Vedas, describes music at length. The Samaveda was derived from the Rigveda so that its hymns could be sung as Samagana; this style evolved into jatis and eventually into ragas. Bharat's Natyashastra was the first treatise laying down fundamental principles of dance, music, and drama.