In 1570 Pope Pius V excommunicated Queen Elizabeth I of England in the papal bullRegnans in Excelsis. This led to the Second Desmond Rebellion in 1579-83, which was still in progress when O'Hurley was required to travel to Ireland. On 11 September 1581, while still a layman, he was appointed Archbishop of Cashel by Pope Gregory XIII. He was ordained and consecrated and set out on his mission in 1583. O'Hurley's voyage was fraught with danger because of the state of war between the Pope and England, but he accepted the risks involved and arranged for a sea captain from Drogheda to smuggle him into Ireland. He disembarked on Holmpatrick Strand in County Dublin in the autumn of 1583. His letters, which had been sent via a different ship, were intercepted by priest hunters. Through its elaborate spy system, the government in Dublin had knowledge of Dermot's appointment to the See of Cashel, and Elizabeth's spies were soon on his tracks. He never reached Cashel. O'Hurley lodged with Thomas Fleming, 10th Baron Slane, at Slane, and from there he spread his activities through the territory of the O'Reilly clan. While sheltering at Slane Castle he was recognised. Under pain of severe penalties Fleming was ordered to arrest O'Hurley who had by then left Slane. O'Hurley was arrested at Carrick-on-Suirin September 1583, while staying with Thomas Butler, 10th Earl of Ormond, a Protestant, referred to as dubh, who was the Lord Treasurer of Ireland at the time. Butler was much offended and distressed at the arrest, and afterwards did his best to rescue O'Hurley from the executioners. On 8 October 1583 O'Hurley was imprisoned in Dublin Castle.
Martyrdom
Upon his arrest, his interrogators claimed that he had been a member of the Roman Inquisition. However, no documents of his activities there survive. Despite severe torture, which included having his legs boiled over a roaring fire, O'Hurley refused to embrace Protestantism. According to surviving correspondence between Dublin and Whitehall, Elizabeth I was reluctant to dispense with a fair trial under English Law, but her mind was changed by Sir Francis Walsingham and she approved of a trial by military tribunal. O'Hurley was tried in a day and sentenced to death. The Chancellor, learning that Butler was coming, by whose influence and power they feared O'Hurley would be saved, determined to put him to death as soon as possible. In the early morning of 19, or 20, June 1584, O'Hurley was taken outside the walls of Dublin and hanged at Hoggen Green. In his last speech, he proclaimed, He was buried in St. Kevin's Church, Camden Row, Dublin. His gravesite remained a site of pilgrimage for many years.
Legacy
As word of his execution spread, O'Hurley was immediately revered as a martyr by Catholics throughout Europe. Several accounts of his life and death were printed and reached a wide audience. Following Catholic Emancipation in the 19th century, Ireland's Roman Catholic hierarchy began an investigation into his life and death. One of the most valuable resources was found to be the documents and letters written by the men who tortured and executed him. In 1904, he was declared a Servant of God. On 27 September 1992, O'Hurley was beatified by Pope John Paul II, alongside 16 other Irish martyrs.
