The rebellion of
Silken Thomas was to involve Barnewall in the delicate task of pleading with Henry VIII for a general pardon on behalf of the Anglo-Irish gentry, many of whom were under suspicion of having supported the rebellion. Barnewall himself apparently had no sympathy for the rebel cause, although his enemy
Walter Cowley tried hard to persuade Cromwell that he had. His uncle Lord Trimlestown had, probably with more reason, been accused of wavering in his loyalty, but Cromwell was evidently prepared to overlook this. Given the close ties of blood and marriage which existed between nearly all the
Anglo-Irish families of
the Pale, it was reasonable that Barnewall, with his considerable influence at the English Court, should be asked by his relatives and neighbours to go to England to plead for a pardon, and he agreed to do so. He was accompanied by Sir
Robert Dillon (died 1580), the
Attorney General for Ireland, who, though technically Barnewall's superior, seems to have been very much the junior partner on the mission. It has been suggested that he was exposing himself to great danger since there was a risk that the King would interpret any plea for mercy as evidence of his support for the rebels. However, he used his influence with Cromwell to good effect, and during his visit to London in 1536-7 he succeeded in obtaining a general
royal pardon for those involved or suspected of involvement in the rebellion. In 1537 he accompanied the
Lord Deputy of Ireland,
Leonard Grey, 1st Viscount Grane, to
Limerick, to assist in a military campaign against the O'Byrnes. == Dissolution of the Monasteries ==