In 1905, Pius X in his letter Acerbo nimis mandated the existence of the Confraternity of Christian Doctrine (catechism class) in every parish in the world.
Pada tahun 1905, Pius X dalam suratnya Acerbo nimis mengamanatkan keberadaan Confraternity of Christian Doctrine (kelas katekismus) di setiap paroki di dunia.