The introduction of Christian pluralism into German society had profound results. Religious conversions of political rulers were common and had widespread implications for subjects and foreigners alike. Religious segregation, rather than toleration, was the rule until the 19th century. Several regions in the north and east developed almost exclusively Lutheran populations, and many localities in the south became overwhelmingly Catholic. Mixed populations, particularly in imperial cities such as Augsburg, did exist, but they were rigidly segregated by religious affiliation.