Kulin Kayasthas are a sub-caste of the Kayastha caste in Bengal, India. They are also known as the Kulina Kayasthas.
The Kayasthas are regarded in Bengal, along with the Brahmins, as being the "highest Hindu castes" that comprise the "upper layer of Hindu society". They are subdivided into numerous clans in that region, of which the Kulin are a high-ranking example.
The caste system in Bengal developed differently from that in neighbouring areas of North India because of the influence of Buddhist rulers in the region at various times up until the eleventh century CE, at which time the Pala dynasty declined. It is traditionally believed that at this point a Hindu king brought in five Brahmins and their five Shudra servants, his purpose being to provide education for the Brahmins already in the area whom he thought to be ignorant. The tradition continues by saying that these incomers settled and each became the founder of a clan. In the case of the five Shudra servants, each clan was of the Kayastha caste.
The five Brahmin clans were each designated as Kulina ("superior") in order to differentiate them from the more established local Brahmins. Four of the Kayastha clans were similarly designated. The fifth was refused the status because they would not accept that they were servants, as was the ritual rank of Shudra, and instead proclaimed themselves to be superior even to the Brahmins. While this fifth clan remained in Bengal and became the Datta (or Dutt) Kayasthas, one of the four which were granted the Kulina nomenclature - the Guhas - later moved to the east of the region, leaving three clans to become the main Kulin Kayastha communities: the Boses, the Mitras and the Ghoshes.
During the Gupta Empire, the Kayasthas had not developed into a distinct caste, although the office of the Kayasthas (scribes) had been instituted before the beginning of the period, this can be made out from the contemporary smritis. In many early epigraphs discovered in Bengal, brahmanic names with large number of modern Bengali Kayastha cognomens can be found, suggesting that a large number of Brahmin communities intermixed with oher varnas to form the present day Kayasthas and Vaidyas of Bengal.
A period of rule by various Muslim dynasties began in Bengal from the thirteenth century and lasted until 1765, when the British gained control. Many of the population converted to Islam and the lack of a Hindu king as a focal point caused the isolation of those Hindu communities which remained. The Kulin communities suffered particularly badly because their ritual role was to serve a Hindu king via appointments to high state and religious offices, which were denied to them by Muslim rule. Those Hindus, including some Kulins, who did assist, co-operate or mingle with the Muslim rulers were often shunned by the increasingly conservative Hindu community, which was intent on self-preservation and withdrew into its own cultural norms in order to achieve that. Thomas J. Hopkins has said that
Similarly, the Kulin castes generally ignored the British who came into the area and eventually took it over. The British were non-Hindu and so they, like the Muslims before them, were unable to satisfy the Kulin need for roles befitting their ritual status. Other Hindu communities, however, did co-operate with the British and by the early years of the nineteenth century some had become substantial landowners and wealthy people as a consequence. These non-Kulin communities also were the first to take steps towards Westernisation, in part because they realised that alignment with Western ideas would provide a route by which they could advance their social status, and that was something which could never occur under the Hindu ritual system as they would always be ranked lower than the Kulins.