[2] Upon the accession of James II in 1685, Maguire travelled to London with Patrick Tyrrell to pledge loyalty to the new king.

[4] During the Williamite War in Ireland, Maguire and other Catholic prelates were instrumental in saving from destruction the valuable library of Trinity College Dublin.

His negotiations with the king encouraged him to convince the Irish Jacobites defenders of Limerick to hold out for much more favourable terms than those which had already been offered by the Williamites.

Through the intercession of Mary of Modena, Maguire secured a pension from Louis XIV, and lived in exile in Paris for the rest of his life.

He died on 21 September 1707,[1][2][3] and was buried in the crypt the church of the Collège des Lombards[6] which was part of the Irish College in Paris.