In April, matters were brought to a head by the arrest of the Reverend William Jackson. An agent of the French Committee of Public Safety, Jackson had been having meetings with Tone in the prison cell of Archibald Hamilton Rowan. Rowan, who had been serving time for distributing Drennan's seditious appeal to Volunteers, managed to flee the country. Whether because of his association with the Catholic Committee or his family's connections, Tone was allowed to go into American exile. Thomas Troy, Catholic Archbishop of Dublin and Papal legate, threatened excommunication for any Catholic who took the United Irish oath and warned his flock to avoid the "fascinating illusions" of French principles. Catholic gentry and clergy withdrew from the Catholic Committee and the United Irish Society was proscribed.