Secondary conversion Wikipedia
In the sociology of religion, secondary conversion is the religious conversion of an individual that results from a relationship with another convert, rather than from any particular aspect of the new religion. For example, someone might join a religious group primarily because their spouse or partner has done so; such a person would be a secondary convert. Secondary converts are people who join a religion only because of a relationship with the other convert.
Secondary conversion can greatly expand a movement's influence, particularly after a conquest, such as the Muslim Moorish conquest of Spain and Catholic Spain's conquests in Latin America.