Thomas Clarkson (1760-1846) was an English abolitionist, and a leading campaigner against the slave trade in the British Empire. He helped found The Society for Effecting the Abolition of the Slave Trade and helped achieve passage of the Slave Trade Act of 1807 which ended British trade in slaves. In his later years Clarkson campaigned for the abolition of slavery worldwide - then concentrated in the Americas. In 1840 he was the key speaker at the Anti-Slavery Society's first conference in London whose aim was to end slavery in other countries. It was at Cambridge in 1785 that Clarkson entered a Latin essay competition that was to set him on the course he was to follow for the rest of his life. The topic of the essay was 'Is it lawful to enslave the unconsenting?' and it led him to consider the question of the slave trade, reading everything he could on the subject, including the works of Anthony Benezet, a Quaker abolitionist, as well as first-hand accounts of the African slave trade. After winning the prize Clarkson had what he termed a spiritual revelation from God and this experience, and sense of calling, led him to devote his life to abolishing the slave trade. He published his Latin essay in English translation as a pamphlet in 1786 and as a result was introduced to others sympathetic to abolition, including James Ramsay and Granville Sharp, many Quakers, and other nonconformists. The abolitionist movement had been gathering strength for some years having been formed by Quakers both in Britain and the US, and in 1783 300 Quakers had presented Parliament with the first petition against the slave trade. Clarkson's involvement gained momentum and he continued to publish essays which provided a grounding for William Wilberforce's first abolitonist speech in the House of Commons in 1789, and his 12 propositions. The war with France delayed any progress on the abolitonist cause but in 1804 Clarkson revived his efforts and was particularly active in persuading MPs to back the parliamentary campaign. In 1808 he published his book History of the Aboliton of the Slave Trade. Two years previously he had written his three-volume A Portraiture of Quakerism, subtitled 'Taken from a View of the Moral Education, Discipline, Peculiar Customs, Religious Principles, Political and Civil Economy, and Character of the Society of Friends'. After his marriage in 1796 Clarkson had renounced his Anglican orders but although most of his political friends were Quakers, he decided against joining the Society of Friends. However, he attended the Penrith Quaker Meeting House with his wife, a former free-thinker, who was described by a friend as 'a species of Quaker', and took a deep interest in their beliefs, an understanding of which he had acquired through his close association with his fellow abolitonists.