Song and dance is at the core of Uyghur cultural identity and is commonly presented at all social gatherings. The most established form of Uyghur music, muqam, has developed since the sixth century into a unique collection of songs and instrumentals, quite separate from Arabic and Persian influence. A muqam must open with a flowing rhythm that complies with strict modal constraints, followed by a suite of pieces that tie into this opening. In the late sixteenth century scholars and folk musicians gathered to collate this music into a definitive collection of twelve muqams. The entire collection takes 24 hours to play and involves around fifteen traditional instruments such as the plucked mandolin-like rawap, metal-stringed dutah and large dumbak drums. Sadly, few people can play muqam nowadays, but recordings are popular and sold on CD and DVD throughout Xinjiang.