He was professor at the Roman College, took part in the revision of the Sixtine Vulgate, and had Hosius and Baronius for literary associates.
His contemporaries called him helluo librorum (glutton of books) for the rapidity with which he examined the principal libraries.
In the last several years of his life, Turrianus had an ongoing battle of books with the French Protestant Antoine de la Roche Chandieu.
He defended the doctrines of the Immaculate Conception, the authority of the sovereign pontiff over the council, the Divinely appointed authority of bishops, Communion under one kind for the laity, the authenticity of the Apostolic Canons and the Pseudo-Isidorian decretals, and pleading the antiquity of the feast of the Presentation of the Blessed Virgin, which Pius V had suppressed, worked for its reinstatement.
He wrote more than seventy books, principally polemical, against Protestants, and translations especially of Greek Fathers, many treatises of whose works he found hidden away in libraries.