This paper examines the historical role of sayyid genealogies in the formation, reproduction and transmission of religious authority in Alevism. Today constituting 15-20 percent of Turkey, which is a Sunni-majority country, Alevis and their Twelver-Imamate Sufi belief, Alevism, have long been topics of debate and controversy. While often deemed as heresy in the early modern Ottoman Empire, Alevism has been subjected to modern reductionism in twentieth-century Turkey, labelled as a folkloric belief. Despite the growing number of studies in the last decades, particularly on modern socio-political and identity issues among the Alevis, there are still a handful of academic works on the religious history of Alevism. This paper contributes to the understanding of Alevism in the early modern period by analysing how Alevi sayyid families, who are called ocak in vernacular Turkish and constitute the religious leadership of Alevi communities, and their genealogies shaped the nature of religious authority among Alevi communities. The paper uses ijazas, shajaras and relevant hagiographical documents as its sources to explore how religious authority was defined, granted, reproduced, and transmitted among the members of Alevi sayyid families in the early modern period. These sources were issued at various Sufi religious centres, such as Karbala, Ardabil, and the town of Haji Bektash in central Anatolia. The documents received from the Sufi lodges in this vast geography demonstrate 1) the significance attributed to these places as centres of religious authority and 2) how the translocal networks of Alevi sayyid families played a role in the reproduction and transmission of religious authority among family members. Examining both the content and spatial dimensions of the above-mentioned sources, this paper analyses the formation and maintenance of religious authority in Alevism.