The active participation of the Roman Catholics in the movement of the United Irishmen was strengthened by the appointment of Tone as paid secretary of the Roman Catholic Committee in the spring of 1792.
At the Worms conference (1540) between Catholics and Protestants he was the sole representative of the Swiss.
For the history of the definition see Vatican Council; also Papacy, Gallicanism, Febronianism, Old Catholics, &c.
Latterly certain Catholics have questioned this equality of the concordatory obligation, and have aroused keen discussion.
He also contributed largely to the Internationale theologische Zeitschrift, a review started in 1893 by the Old Catholics to promote the union of National Churches on the basis of the councils of the Undivided Church, and admitting articles in German, French and English.