As both men were Catholics in a Protestant country, Petre soon found favour with the new King.
His second cousin, Father Edward Petre, S.J., became advisor and confidant to James II.
After James's flight in the Glorious Revolution, Petre was forced to resign when the militia refused to serve a Catholic.
After the Revolution, much of the vast revenues from the Petre estates were sent abroad to help maintain those institutions in continental Europe that provided education for Catholic Englishmen.
He died on 10 January 1706, and was succeeded by his only son Robert, by which time the family had fully recovered financially.