Baidya or Vaidya is a Hindu caste community of Bengal. The Baidyas have generally claimed Brahmin status, but some have been associated with the Ambashtha caste or sub-caste. In the pre-colonial era of Bengal, Baidyas were regarded as the highest Hindu castes along with Brahmins and Kayasthas.
Historian Bijay Chandra Mazumdar suggests that the Baidyas owe their origin to the Vellala Vaidyas, known for their military prowess in Southern India, who started functioning as Brahmins some time earlier than the 10th century CE, and originally got the designation ‘Vaidya’ on account of their knowledge and study of the Vedas. The Vellala Vaidyas also served as military leaders and high civil officers apart from being priests of the Dravidian kings.
These migrants, probably Ambashthas as well as the other groups like Vellala Vaidyas, started moving from north and south to Bengal during the period of the Pala Empire. They mainly dealt with medicine and other fields of study. Some of them rose to power and endeavoured to revive Vedic Hinduism in predominantly Buddhist Bengal. According to Ronald Inden, Adisur and Vallal Sena of Sena dynasty were considered as Vaidyas. Inden also mentions the Vaidyas as “one of the highest of the Shudra castes”, who possessed “one of the Vedas”, the Ayurveda. However, they were considered as one of the highest among the Hindu castes in Bengal, and there are instances where they were not considered as Shudras; like Calcutta Sanskrit College, where Shudras were debarred from admission, initially allowed only Brahmins and Baidyas to enroll until Ishwar Chandra Vidyasagar introduced the admission for Kayasthas; other Shudra castes were not allowed to study.
Most Baidyas perform rituals like wearing the sacred thread. It is believed that Vallal Sen, the legendary Sena king, divided the Baidyas into two divisions, for one of which wearing of the thread was compulsory and for the other it was optional, while some consider that a section of the Baidyas themselves started wearing the sacred thread in the 18th century when they started movements in order to improve their ritual status. Tej Ram Sharma, an Indian historian, says that
Originally the professions of Kayastha (scribe) and Vaidya (physician) were not restricted and could be followed by people of different varnas including the brahmanas. So there is every probability that a number of brahmana families were mixed up with members of other varnas in forming the present Kayastha and Vaidya communities of Bengal.
Traditionally, the Brahmin, Baidya and Kayastha communities together formed the second tier in the social hierarchy of Bengal, being ranked below the rulers. In the era of the Palas, Senas, Pathans and Mughals, the ruler had to rely on their support. Baidyas shared the knowledge of Sanskrit with Brahmins. These three castes held major landholding and control over education and major professions.
The terms Baidya and Vaidya also literally mean a physician in the Bengali and Sanskrit languages