Singulari Nos (which was subtitled On The Errors Of Lammenais) was an encyclical issued on June 25, 1834 by Pope Gregory XVI Essentially a follow-up to the better-known Mirari Vos of 1832, Singulari Nos focused strongly on the doctrinal errors of French priest Hughes Felicité Robert de Lamennais, who did not see any contradiction between Catholicism and then-modern ideals of liberalism and the separation of Church and State.