Following the collective foreigner from the potential threat that he represented to crown interests, over the various hurdles to acceptance, and on to his death reveals a great deal about both the immigrants and the Spaniards. In the first place, foreign residents of New Spain in the first half of the eighteenth century represented neither a major threat nor an indispensable asset to the viceroyalty. On balance their presence was more positive than negative. Many brought skills, established families, and became loyal subjects of the crown. They were, or they became, or, at least, they pretended to be good Catholics. They did not introduce subversive ideas, and their limited economic impact seems to have been largely internal to New Spain, consonant with the values of the society in which they had come to live, and devoid of direct links with their mother countries.

In most cases forbidden to be in the Indies at all, foreigners entered the official record for a variety of reasons. Some represented religious deviation or social problems, but almost as often they appeared as nothing more than witnesses or interpreters. In wartime, colonial authorities occasionally sought out natives of enemy countries, sometimes because of feared subversion, but more likely from a desire to seize their wealth. The same officials or their superiors, however, almost invariably released those aliens discovered in the round-ups. Real enemies were usually only a few poor prisoners of war captured elsewhere and interned in New Spain.