After revolutions in Russia, China, and Mexico had been followed by religious persecution, a new theme of criticism was added, beginning with Quadragesimo anno (1931) by Pope Pius XI.
Setelah revolusi di Rusia, Cina, dan Meksiko disusul oleh penindasan keagamaan, sebuah tema baru dari kritikan ditambahkan, bermula dengan Quadragesimo anno (1931) buatan Paus Pius XI.