Your challenge is to have at least one country's population be mostly followers of the Bahá'í Faith by 1950. This doesn't have to be a large majority, 51% will do.
Before anyone asks, I posted this in Before 1900 because I think this would be more feasible with an earlier POD.
Before anyone asks, I posted this in Before 1900 because I think this would be more feasible with an earlier POD.