Thomas Clarkson
![Thomas Clarkson by [[Carl Frederik von Breda]], painting in the [[National Portrait Gallery (London)|National Portrait Gallery]]](https://upload.wikimedia.org/wikipedia/commons/9/90/Thomas_Clarkson_by_Carl_Frederik_von_Breda.jpg)
He became a pacifist in 1816 and, with his brother John, was among the twelve founders of the Society for the Promotion of Permanent and Universal Peace.
In his later years, Clarkson campaigned for the abolition of slavery worldwide. In 1840, he was the key speaker at the British and Foreign Anti-Slavery Society's first convention in London which campaigned to end slavery in other countries. Provided by Wikipedia