A zealous promoter of strict observance, he also held offices in the Order and was a co-founder of the University of Dillingen (1549), where he taught theology (1549-55). Invited by Cardinal Pole, he taught at Oxford (1556). He examined the Catechism of Carranza, defending II. On 9 May 1561 Pius IV appointed him his theologian at the Council of Trent, where he upheld the divine right of episcopal residence and jurisdiction.
Prudent and skilled as a diplomat, he often acted as intermediary between the Emperor and the Pope. He contributed to the Peace of Crépy between the Emperor and the King of France and took part in the Diet of Augsburg. He left various works of a catechetical and polemical nature: *Institutiones Christianae* (Augsburg 1548); *Compendium doctrinae catholicae* (Ingolstadt 1549, and many other editions); *Methodus Confessionis* (Antwerp 1550; Dillingen 1553); *Assertio catholicae fidei* (Cologne 1555); *Tractatus de institutione sacerdotum* (Dillingen 1558, long used as a manual at the University of Dillingen); *Defensio catholicae religionis* (Antwerp 1557).