Richard Lewis was born in Wales in 1808. He was commonly niknamed Dic Penderyn, for Penderyn Village, where he had been living.  He was hanged in 1831 at the age of 23 as a consequence of his participation in a labor uprising. The banner of the workers was a red flag; this is said to be the first time in history that it was so used.  As a point of historical context, Karl Marx was five years old when Dic was hanged.
Dic, like his father, was a coal miner. His family moved to Merthyr Tydfil so that Dic's father could work in the mines there. Dic himself was intelligent and outspoken, and was thought to be a union leader.
The "Merthyr Rising" of 1831
Workers took control of the village of Merthyr Tydfil, and held it for a week. This was the first "politicized" workers uprising in the history of Britain.
It wasn't hard to find causes for the rebellion. The working conditions in the mines and iron works were terrible. Compounding the bad conditions, wages were being cut, and there were layoffs due to falling demand for both iron and coal at that time.
Exacerbating the poor wage situation, the companies were paying workers in kind, not in cash, and provided goods to the workers through "truck shops". With less than a living wage, workers found themselves with ever increasing debt loads; in effect, as in other situations where payment was in scrip which could only be redeemed at the company store, the payment arrangements turned the miners from free men into indentured workers.
Workers took control of the government buildings, and ransacked the building containing the debt records. The village had no police force, and frightened authorities eventually brought in Highland Scots soldiers to put down the rebellion.
On 3 June 1831, a crowd of rioters and soldiers confronted each other in front of the Castle Inn in Merthyr Tydfil. There was fighting, and other soldiers, inside the inn, fired through the windows into the crowd. Sixteen people were killed and many more wounded. There may have been additional deaths from the injuries later on.
No soldier was hit by any bullets, as the crowd was unarmed. Only one death was ever investigated, that of John Hughes. The inquest found unanimously that his death was justifiable homicide. A civilian who injured a soldier received the death penalty, but soldiers who murdered 16 civilians were excused.
One soldier was injured during the fight. Donald Black was stabbed in the leg by a bayonet. The bayonet was attached to a soldier's gun; it's said that it was "probably dragged off a soldier" in the struggle and then wielded by a rioter. However, Black never saw the person who injured him, so it's not entirely obvious how he could even have been sure it wasn't an accidental injury by another soldier in the confusion of the fight.
Dic Penderyn's Role in the "Merthyr Rising"
Dic Penderyn was apparently present, and was considered to be a leader of the workers, but it's not clear if he played a role in the uprising. No conclusive evidence to that effect was ever presented. None the less, he was singled out, probably because of his union activism. 
In fact, Lewis Lewis, Dic's cousin, seems to have been the leader of the rebellion.
Dic Penderyn was accused of having stabbed Donald Black during the riot. He was tried and convicted, and sentenced to death.
Lewis Lewis was also sentenced to death for his role in the uprising, but when it was found that he had protected a constable from the angry crowd his sentenced was commuted to transportation for life.
A petition was circulated asking for clemency for Dic, and was said to have had 11,000 names on it. Furthermore, a Quaker ironmaster named Joseph Tregelles Price started a campaign to establish Dic's innocence and get him a reprieve. In fact, even the trial judge who had convicted Dic eventually became convinced of his innocence, but by that time the case was in the hands of the government, and the Home Secretary, Lord Melbourne, refused to listen to any arguments for Dic's innocence. Thus, Dic's execution was blatantly a matter of policy, not justice.
- [http://www.bbc.co.uk/blogs/wales/posts/dic_penderyn_the_welsh_martyr BBC: Dic Penderyn, the Welsh Martyr].
- [http://www.100welshheroes.com/en/biography/dicpenderyn Welsh Heroes: Dic Penderyn (Richard Lewis)].
- [http://www.alangeorge.co.uk/dicpenderynsociety.htm Dic Penderyn Society].
- [http://www.benybont.co.uk/another/dic.htm Raymond Humpreys: Dic Penderyn].