During the Second World War, the Roman Catholic Church protested against Action T4, the Nazi involuntary euthanasia programme under which the mentally ill, physically deformed, and incurably sick were to be killed. The protests formed one of the most significant public acts of Catholic resistance to Nazism undertaken within Germany. The programme began in 1939, and ultimately resulted in the murder of more than 70,000 people who were senile, mentally handicapped, mentally ill, epileptics, cripples, children with Down's Syndrome or people with similar afflictions. The murders involved interference in Church welfare institutions, and awareness of the murderous programme became widespread, and the Church leaders who opposed it – chiefly the Catholic Bishop August von Galen of Munster and Prot