Lord Byron

Lord Byron (5 Nov 1722 - 19 May 1798) -- great uncle of the poet, killed a Mr. Chaworth in a duel and was tried in the House of Lords.

"On 26 January 1765, Lord Byron killed his cousin and neighbour, William Chaworth [broken link to Wikipedia], in a duel at the Stars and Garters Tavern in London. The fight resulted from an argument the two had been engaged in over cups of wine, with both insisting they had more game on their estates. Lord Byron and his cousin retired to a dim room to resolve their disagreement and it was there that Lord Byron thrust his sword through Chaworth's stomach. Chaworth lived until the following day, expressing his disgust that he had not been of sound enough mind to insist they fight in a location outfitted with better lighting before finally succumbing to his injury. Lord Byron was tried for Chaworth's death, but under the Statute of Edward VI [broken link to Wikipedia] he was found guilty only of manslaughter and forced to pay a small fine. Upon returning home to Newstead Abbey, he mounted the sword he used to kill Chaworth on the wall in his bedroom. It was at this time in his life that he was nicknamed "The Wicked Lord", a title he very much enjoyed."

More here.