Soon after World War II, the 1951 U.N. Refugee Convention, a legally binding multilateral treaty, defined who is a refugee, what rights they have, and established the obligations of nations in their regard. In the broader field of migration, however, apart from a convention on migrant workers, until now there has been no comparable international agreement regarding migrants in general.
In 1951, the International Organization for Migration (IOM) was established as an intergovernmental organization, working with governmental, intergovernmental and nongovernmental partners to provide a wide variety of services in the field of migration. The IOM joined the U.N. system in September 2016.
In 1952, Pope Pius XII published the apostolic constitution Exsul Familia, the magna carta of the Church’s commitment to migration; it gives the diocesan bishop the leading responsibility for the pastoral care of migrants. A year earlier, in 1951, Pius XII founded the International Catholic Migration Commission (ICMC) as a global network of episcopal conferences, religious congregations and Catholic NGOs.