This article explores the evolution of naturalization in Western Europe and the United States from the early modern period to the end of the nineteenth century. It discusses three phases: naturalization as an economic privilege in the early modern period; naturalization as a grant of political rights reserved for a minority of the population; and naturalization as access to membership to a community of equals. It argues that naturalization, while mainly relevant to individuals moving from one country to another, also involved aspects of multilateralism throughout: naturalized citizens possess a status negotiated by their original and new states of membership, but this status can also be of great relevance in interaction with third countries.
Andreas Fahrmeir, Citizens in limbo. naturalization concepts between privilege and membership in 19th-Century Western Europe and the United States, Citizenship Studies, 2021.