 Traditional Sikhs use quotations by Bhai Gurdas, whose "Vaaraa," or "Ballads," were considered by Guru Arjan as a key to understanding the concepts of the Guru Granth Sahib as saying, wherever Guru Nanak went and debated the futility of yoga, the yogis gave up at least some ritualistic aspects of their yogic paths.The yogis of "Gorakhmatta," meaning "Wisdom of Gorakhnatha," the founder of Hatha yoga, converted to the path of Guru Nanak, and also changed the name of their ancient center to Nanakmatta meaning "Wisdom of Guru Nanak," known today as Gurdwara Sri Nanakmatta Sahib.Some claim yoga is refuted in the Guru Granth Sahib, or that Guru Nanak never practiced yoga and neither did any of the following Gurus, their Sikhs or the Khalsa.