Medievalism (PDF)

In his Lenten pastoral letter of 1908, Cardinal Mercier, the primate of Belgium, attacked Modernism and George Tyrrell as its leading exponent, and then distributed it as a pamphlet. This volume includes the text of the pastoral letter (in English and in French) and Tyrrell's response. Tyrrell takes on the Cardinal's attack point by point on tradition, bishops, papal authority, heresy, Kant, Darwin,

Since you have thought fit to mention me by name in your Lenten Pastoral (1908) as the most typical embodiment of the Modernism which you are there denouncing; since you profess to draw your description of that movement from my writings; since your Pastoral has received the special commendation of the Holy Father; and since you have now chosen to give it the permanent and wider publicity of a brochure, you can hardly wonder if I assert the inalienable right of every man to speak in the defence of what he believes to be the truth. . . .
I am not ashamed of 'Modernism.' When you speak of me as 'the most penetrating observer of contemporary Modernism . . . the man most profoundly imbued with its spirit, I should feel flattered were I coxcomb enough to believe myself level with those leaders of the movement whom I follow, from whom I have learnt everything, and from whom I have yet so much to learn. But, for Your Eminence, Modernism is the deadliest of heresies, and heresy the deadliest moral obliquity; and of this obliquity you present me, first to Belgium, and now to the world, as the most deeply imbued representative. Seeing it was quite necessary, I can hardly think it was friendly, or even charitable, to take such uncalled-for action, which would have come much better from the Archbishop of Westminster. It is in England and not in Belgium that I am kinown and read.
--from the Introduction