True, there is a certain ritual among some dervishes, and they trace it to the time of Jelal-ud-Din Rumi, our great Persian poet. They relate how once this poet, absorbed in the thought of all life as one beauty, in the thought of the motion and rhythm of life, he turned himself in a circle, he circled around; and the movement which the skirt of his garment made as it whirled, brought such a beautiful picture before him and his pupils, that they stored it in their memory ever after. So the dance celebrates this memory.