In 2003 I published a book on citizenship and belonging in Spain and Spanish America. Having surveyed hundreds of conflicts in which individuals requested rights (or were forced to comply with duties) either in local communities or in the kingdom, I discovered that both litigants and those who opposed them, both local and royal authorities, both jurists and laymen, referenced a similar set of criteria. According to it, status, rather than being automatically abstracted from birth or descent, hinged upon the ability to demonstrate attachment to the community. Attachment could be demonstrated in multiple ways: local residence, marriage to a local person, owning of real estate, or paying taxes. Although a legal presumption protected those born locally to locally born parents –in their case the presumption held that they loved the community and were loyal to it— if there was reason to believe the contrary, then despite local birth to locally born parents, these individuals would be considered foreign. The same was true of those born outside to foreign parents. In their case, the presumption held that they had no love to the community. But if they could demonstrate that they did (by referencing the indications enumerated above that demonstrated integration) then they would be recognized as members.
In both Spain and Spanish America, these categories operated vis-à-vis both the local community (constituting individuals as vecinos) and the kingdom community (recognizing them as naturales). Initially, each Spanish kingdom had its own community of natives, which was distinguished from others (there were natives of Castile, natives or Aragón, and so forth). However, by the late sixteenth century, the category “natives of the kingdoms of Spain” also made its appearance. First applied in the Americas, where only “natives of Spain” could theoretically reside and undertake commercial activities, by the early eighteenth century this category was also applied in the Iberian Peninsula. Thereafter, legally, at least, there was only one community of natives in Spain and it included all Spaniards.
My aim in pursuing these questions was to write a history that would observe NOT how states and kings defined members but how residents engaged in the elaboration of a legal distinction between natives and foreigners, Spaniards and aliens. Rather than discovering what the law meant, I was after the question how historical actors used the law and how this use influenced what they said and what they did. I also wanted to re-think debates regarding citizenship. These debates affirmed the importance of medieval urban citizenship to the formation of state centered citizenship, but normally failed to explain how these processes of borrowing and extension took place. Spain and Spanish America gave an interesting answer because they demonstrate that to determine who Spaniards were people asked about their urban membership. If the literature tended to affirm that there were no citizens in monarchical territories, my wish was to showcase their importance. Methodologically, I was interested in reconstructing the legalities of the past not by referencing abstract legal doctrines, jurisprudence, or legislation, but instead by analyzing the words and behavior of a multiplicity of actors. Undertaking a task similar to the one linguists perform when they analyze speech to reconstruct the rules that govern it, I wanted to understand how contemporaries conceived of membership. Why did they think they had rights? How did they explain their refusal to allow others to enjoy them? I was also fascinated by the need to reconstruct rules by observing conflict. I asked: what do moments of disagreement tell us about consensus? How can we learn from them what happened when people agreed?
In chapter 8 of that book I engaged with comparative research. I asked whether if we applied the same questions and methodology to England, France, and Italy, we would reveal similarities. Because I could not carry out the same detailed archival research in my comparative examples, I decided to focus instead on examining the secondary literature.
The historians whose work I read affirmed that membership in England, France, and Italy was radically different than what I have discovered in Spain and Spanish America. Yet, as I read through their scholarship I found plenty of indications that such might not have been the case. Municipal and kingdom communities also existed in England, France, and Italy and, in most of the cases I reviewed, membership in them implied the imposition of a certain regime of privileges and duties. In all these places, obtaining status as member was contingent on behavior, which could be formally recognized by the competent authorities or implicitly acquired through prescription. Behaviors recognized as meaningful were also extremely similar: permanent residence and tax payment ranked high but so did marriage to a local or the purchase of real estate. Local birth to locally born parents could be significant on occasions, but it was mostly treated as a legal presumption, not a condition sine-qua-non. Prima-facie, England did look somewhat different because of the tying of freedom to the exercise of certain professions. Yet, in the early modern period, freedom and Continental citizenship came to be closely associated, most clearly in the ruling of common law courts. Similarly, if subjecthood in England seemed divergent when observed through the famous Calvin Case, it stopped being thus if analyzed, for example, by studying how imperial subjects negotiated status as Englishmen.
I thus concluded that similarities between the Spanish, Italian, French, and English experience might have been much greater than is currently accepted and that that there was, in fact, a common European framework that operated across the continent despite the existence of local variations. As a historian of Spain, I thus wondered: Can Spanish history be normalized rather than exoticized (as it usually is)? Can it be made central to narratives of European (and legal) formation? Can we converse across national historiographies to imagine a common European past or is this attempt doomed to fail? How to overcome a tendency to highlight particularities rather than to search for what we share?
 Tamar Herzog. Defining Nations: Immigrants and Citizens in Early Modern Spain and Spanish America. New Haven: Yale University Press, 2003; Vecinos y extranjeros. Hacerse español en la edad moderna. Madrid: Alianza Editorial, 2006; Nations, Citoyens, Immigrés dans L’Espagne et l’Amérique espagnole du XVIIIe siècle. Paris: Le Poisson Volant, 2017.
 On these issues, see the most recent Hannah Weiss Muller. Subjects and Sovereign: Bonds of Belonging in the Eighteenth-Century British Empire. New York: Oxford University Press, 2017 and my review, published in the William and Mary Quarterly 75 (1) (2018): 179-182. Also see Daniel J. Hulsebosch. “English Liberties Outside England. Floors, Doors, Windows, and Ceilings in the Legal Architecture of Empire.” In Lorna Hutson ed. The Oxford Handbook of English Law and Literature, 1500-1700. Oxford: Oxford University Press, 2017, 748-772.