Sir Thomas Wyatt the Younger (c.1519-1554) was an English soldier who fought in the Italian Wars before returning to England, where he led a dangerous revolt against Mary I.
Wyatt was the son of the diplomat Thomas Wyatt the Elder. The son had a more turbulent reputation. In 1543 he was imprisoned for his part in a riot, and later in the same year he left the country to seek military adventure abroad. Despite his troubles with the law he fought with Henry VIII during the successful siege of Boulogne (19 July-14 September 1544).
After a successful career, mainly in the French service, Wyatt returned to England in 1549 or 1550. He was appointed sheriff of Kent in 1551, and he used his experience to create a military structure in the county.
In July 1553 he supported the succession of Mary I. He began to turn against her when she prepared to marry Philip II of Spain. Wyatt felt that this went against England's honour. The Spanish marriage wasn't popular, and Wyatt was able to find other plotters, amongst them the Earl of Devon.
In January 1554 Devon revealed the plot to the Lord Chancellor, Stephen Gardiner. Most of the leaders were arrested, but Wyatt managed to raise an army in Kent. Mary sent Thomas Howard, duke of Norfolk, to deal with this threat, but his army deserted to Wyatt.
On 3 February 1554 Wyatt entered London at the head of 3,000 men. Mary was able to rouse popular support for her cause, and London failed to rise against her. Wyatt's men fought a short skirmish in the city, but Wyatt then surrendered. He was tried and condemned on 15 March and executed on 11 April 1554. In his last months Wyatt had come under great pressure to implicate Mary's sister Elizabeth in the plot, but refused. The failure of Wyatt's revolt ended open opposition to Mary's marriage to Philip of Spain, but as Mary's popularity faded Wyatt began to be seen as a martyr.