To turn Roman Catholic was the best recommendation to favour both at Whitehall and at Dublin Castle.
Clancarty speedily changed his religion, and from a dissolute Protestant became a dissolute Papist.

After the Revolution he followed the fortunes of James; sate in the Celtic Parliament which met at the King's Inns; commanded a regiment in the Celtic army; was forced to surrender himself to Marlborough at Cork; was sent to England, and was imprisoned in the Tower.

The Clancarty estates, which were supposed to yield a rent of not much less than ten thousand a year, were confiscated.

They were charged with an annuity to the Earl's brother, and with another annuity to his wife; but the greater part was bestowed by the King on Lord Woodstock, the eldest son of Portland; During some time, the prisoner's life was not safe.

For the popular voice accused him of outrages for which the utmost license of civil war would not furnish a plea.