Religious conversion and coexistence are concepts at the forefront of contemporary political debates in the subcontinent. Political actors are currently mostly busy wielding distinctions such as indigenous vs. foreign and playing a dangerous game of exclusion and assimilation. Our one-day conference gathers together senior and junior scholars working on a common project which explores a longue durée history of practices and concepts when religious plurality thrived in one of the most travelled maritime regions of the world: the Indian Ocean and south India. From antiquity until the late eighteenth century, this region was a crucial link in a unified world economy and maritime culture. It was also the theater of encounters and circulation of religious actors, objects and ideas between the Mediterranean and West Asian Messianic religions - which we are accustomed now to call, with a Muslim term, Abrahamic - and Indian religious traditions and philosophical systems. We are in particular interested in multi-religious community formation and its effects on political dynamics in the region. State-building, development of new or refurbished local cults, the flowering of multilingual literary forms were only some of the consequences of the early modern political and cultural innovations directly linked to a certain degree of socio-religious mobility created in the multi-religious context of the immediate pre-British colonial period. The hardening of communal boundaries however started also precisely at this moment, and the colonial rule only quickened the creation of “fixed” social and religious categories of caste and religion. In the process the category of Abrahamic religion (Christian, Muslim, Jews) slipped through the British colonial knowledge grid into a “western”, non-Indian religion and thus conceptually unworthy of studying in the “area studies” context. Through this move a whole range of pre-colonial knowledge forms were left invisible and discarded. The final assault on multi-religiosity came from the 19^th century revivalist/nativist and purifying efforts of the social and religious reformers who thus tried to cut down inter- and intra-religious networks in the name of ancient history, immobile orthodoxy and new ideological constructs of nation-state and Hinduism.