)In 1883, when the archbishops of the United States were invited to Rome to prepare for the Third Plenary Council of Baltimore, they took Dr. Corcoran with them as secretary, and, at their request, he was permitted to be present and take notes at the sessions held with the three cardinals appointed by Pope Leo XIII as a special commission.The following year he was made a domestic prelate and assisted as secretary at the Plenary Council.