भस्म-धारणम्

Indo European provenance

Bhasma dhAraNa is atleast from Indo-Iranian period if not Indo-European. There’s attestation of smearing ash from “fire of verethraghna”. (Page 59 of Dastur Erachji Sohrabji, Meherjirana, E. S. D. (1982). A guide to the Zoroastrian religion : a nineteenth century catechism with modern commentary, N Brockman)

The Lent practice of putting ash on forehead is most likely a pagan imitation (and called out as such by other preta denominations). Given the context it’s most likely a Germanic practice.

Hindu provenance

Mantras to do bhasmadhāraṇa are from the śruti. From Atharvaśiras “अग्निरिति भस्म वायुरिती भस्म…". Bhasmadhāraṇa is so closely associated with Vaidikam that even lokāyatas mocked them as अग्निहोत्रं त्रयो वेदास्त्रिदण्डं भस्मगुण्ठनम्।

In some kumbhakoNa rescension texts of mahAbhArata’s anushAsanaparva- आयुष्कामो द्विजो देवि धारयेद्भस्म नित्यशः । In the Padma Purāṇa, Śrī Rāma also dons the Bhasma as per the rites taught by Śrī Agastya, after which the Śiva Gītā is revealed.

Śaṅkara Digvijaya: “त्रिपुण्ड्रं तस्याऽऽहुः सितभसितशोभि त्रिपथगां..”. The dvaitin Nārāyaṇa Paṇḍita also assails Advaitins as those who don Bhasma. In his Maṇi Mañjari there is an episode of evil Māyāvādins harassing Vaiṣṇavas as forcing them to change their “marks”.