Latin Lexicon of Benjamin Hedericus, which still holds its place in the Italian colleges; he also edited the Acts of the congregation in seven quarto volumes, as well as other important works. Rector of Pontifical Irish College In late 1831, Cullen was appointed rector of a fledgling and struggling Irish College. He successfully secured the future of the college by increasing the student population and thereby strengthening the finances of the college. He astutely fostered relationships with the Irish hierarchy, on whom he relied for students, often becoming their official Roman agent. This role yielded income and influence and was to remain a key function of future rectors. He endeavoured to chart a middle ground between conflicting parties of Irish bishops. He was active in his opposition to the establishment of the secular Queen's Colleges. During the revolution that saw the authority of the Papal States violently displaced for the short lived Roman Republic, he accepted the position of rector of the College of Propaganda while retaining charge of the Irish College. As all the rectors of Colleges in Rome, who were not foreigners, had to leave the city, Cullen was left in charge, temporally, of their interests. Soon after his appointment the Revolutionary Trimuvirate issued orders that the College of Propaganda was to be dissolved and the buildings appropriated. The rector appealed to Lewis Cass Jr., the chargé d'affaires of the United States diplomatic mission, to protect the citizens of the United States who were students of the college. Within an hour, the American flag was floating over the Propaganda College. The order of confiscation was withdrawn. Cass was subsequently criticised for his actions. Armagh and Dublin Cullen was appointed Roman Catholic Archbishop of Armagh on 19 December 1849 and consecrated by the Cardinal Prefect of Propaganda at the Irish College in Rome on 24 February 1850. He was also named Apostolic Delegate. His first major act as Archbishop of Armagh was to convene the Synod of Thurles (1850), the first Roman Catholic national synod held in Ireland since the Reformation. It occurred during the period of the debilitating Irish Famine which reduced the population of the country by over 2 million people through starvation, disease and emigration. The purpose of the synod was to establish a new ecclesiastical discipline in Ireland. This included rules relating to the celebration of Mass, the administration of the sacraments and the maintenance