This was the session of the Council attended by the last Catholic Bishop of St. Asaph's, Thomas Goldwell. He had been appointed by Mary I and he gave the last rites to Reginald Cardinal Pole, but had to go into exile at the beginning of Elizabeth I's reign without ever really becoming the ordinary of his diocese in Wales. As the Catholic Encyclopedia explains:
He was the only English bishop at the Council of Trent, where he was treated with marked respect. He was there engaged in the revision of the Breviary and the Missal; and also urged the council to excommunicate Queen Elizabeth. His mere presence at Trent was a cause of such excessive annoyance to Elizabeth that she wrote the following extraordinary farrago of falsehood to her German envoy Mundt: "We think it may be that one Goldwell, a very simple and fond man, having in our late sister's time been named to a small bishopric in Wales called St. Asaph, though never thereto admitted, flying out of the realm upon our sister's death, is gone to Rome as a renegade, and there using the name of a bishop, without order or title, is perhaps gone in the train of some Cardinal to Trent, and so it is likely the speech hath arisen of a bishop of England being there."
Not only did Thomas Goldwell attend the third session of the Council of Trent, but he was active in implementing its reforms:
In 1563 Goldwell was vicar-general to the Archbishop of Milan, St. Charles Borromeo. In 1567 he was made vicar of the cardinal archpriest in the Lateran, and in 1574 the Cardinal Vicar Savelli made him his vicegerent; he thus became, so to speak, the "working" bishop of Rome. . . . One of the last acts of his long and strenuous career was to serve on the Congregation for the Revision of the Roman Martyrology, in 1582. On the death of the Bishop of Lincoln, in 1584, Goldwell became the sole survivor of the ancient English hierarchy. He died the next year [on April 3], and was buried at St. Sylvester's.
He had even tried to accompany St. Edmund Campion, Father Robert Persons, et al on the mission to England in 1580 but became too ill during the journey on the Continent from Rome to the coast. He had to turn back at Reims.