11‭ June 1534: The Revolt of Silken Thomas on this day. Lord Thomas Fitzgerald or ‘Silken Thomas’ as he was more popularly known, was a young man of just 21 years of age when he rode through the streets of Dublin with a large band of followers, and entered the Chapter House of St. Mary's Abbey [above] * where the King's Council were awaiting him.

Whereupon with his brilliant retinue of seven score horsemen he rode through the streets to St.‭ ‬Mary's Abbey‭; ‬and entering the chamber where the council sat,‭ ‬he openly renounced his allegiance,‭ ‬and proceeded to deliver up the sword and robes of state.
From A Concise History of Ireland by P.‭ ‬W. Joyce

His father was none other than Garret Óg,‭ ‬the Earl of Kildare,‭ ‬the most powerful man in Ireland. In his father’s absence in England to answer charges against his name Lord Thomas had been appointed the King’s Deputy in his place. But false rumours that Henry VIII had executed Garret Óg reached his ears. He concluded, without waiting to check the veracity of this information, that his father was indeed dead. He felt that no time could be lost in staking out his claim to lead the Catholics of Ireland in opposing Henry and his now openly Protestant Court. He that day renounced his stewardship of being the King’s Deputy in Ireland and declared himself no longer bound to King Henry VIII by word or deed.

Henry VIII treated his defiance of Royal Power as an act of open revolt and confined Garret Óg to the Tower of London,‭ ‬where Garret died two months later. After a bloody Revolt that lasted into 1535 Silken Thomas gave himself up when his forces were defeated and conveyed to London for Trial. He too was placed in the Tower and held in wretched conditions. He wrote home from that place of cold captivity a letter full of pathos:
I never had any money since I came into prison,‭ but a noble, nor I have had neither hosen, doublet, nor shoes, nor shirt but one; nor any other garment but a single frieze gown, for a velvet furred with budge [i.e. instead of a velvet furred with lambskin fur], and so I have gone wolward [shirtless] and barefoot and barelegged divers times (when it hath not been very warm); and so I should have done still, but that poor prisoners of their gentleness hath sometimes given me old hosen and shoes and shirts.‬
P.‭ ‬W.‭ ‬Joyce

The unfortunate Silken Thomas,‭ ‬born into a life of wealth and privilege, eventually was sent to the gallows. He was hanged alongside five of his captured uncles at Tyburn,‭ ‬London in February 1537. His epic Revolt marked the start of a series of Wars by the Irish against the growing power of a centralised Monarchy committed to enforcing English Royal Rule and the Protestant Religion in this Country.

* The entrance to the Meeting House is on Meeting House Lane off Marys Abbey in Dublin City Centre. It is all that remains of the great Medieval Monastery that stood on that site for centuries.