IAJO (LE JAY), CLAUDIO. - Theologian, controversialist. He was born around 1500 in Mieussy (Savoia) and died in Vienna, Austria, on 6 August 1552. Having obtained at the Sorbonne (1534) the degree of Master of Arts and being ordained priest, he joined the newly founded Society of Jesus at Montmartre on 15 August 1535. In 1537 he went to Italy, where he met St Ignatius of Loyola and took part in the first apostolic activities directed by him, especially in Rome and Ferrara, reconciling the inhabitants of Bagnoregio and Brescia, divided into factions, and reforming morals in Faenza.
In 1542 he left for Germany, where at Speyer and especially at Regensburg he distinguished himself as an orator and controversialist, threatened with death by heretics but respected for his noble life and courage. In 1543-44 he worked at Ingolstadt, Dillingen and Worms; he took part with St Peter Canisius in the Diet of 1545; in the same year he was sent by Cardinal Otto von Truchseß as his representative to the Council of Trent, which he attended during its transfer to Bologna and Ferrara (1545-1549).
Meanwhile, King Ferdinand of Austria proposed him as Bishop of Trieste, but Iajo declined, and Duke William IV of Bavaria requested him from Pope Paul III for the restoration of the University of Ingolstadt. In Vienna he founded the Jesuit College.
The immense success of his work among Protestants is attributed by his biographers to his distinction and modesty, combined with frankness, simplicity and affability, as well as to his irreproachable conduct and priestly virtues.