 In theory, the Chatharīyas of the Kathmandu Valley do not call on other Brahmin group, as Rajopadhyayas alone serve as their historical purohits and perform all their life-cycle Sanskara rituals, including attaining their Gayatri Mantra verse and the sacred thread ('janai') in the Upanayana ceremony.This is opposed to all other clean-caste Newar groups who call upon a Buddhist Vajrāchārya as their family priest to conduct all life-cycle ceremonies.Rajopadhyayas are an endogamous Brahman group who are the descendants of Kānyakubja Brahmins of Kannauj who immigrated to Kathmandu Valley as late as the 16th century CE.