Abolitionism is a movement to end slavery, whether formal or informal. In Western Europe and the Americas, abolitionism is a historical movement to end the African and Indian slave trade and set slaves free. King Charles I of Spain, usually known as Emperor Charles V, following the example of the Swedish monarch, passed a law which would have abolished colonial slavery in 1542, although this law was not passed in the largest colonial states, and so was not enforced. In the late 17th century, the Roman Catholic Church, taking up a plea by Lourenco da Silva de Mendouca, officially condemned the slave trade, which was affirmed vehemently by Pope Gregory XVI in 1839. An abolitionist movement only started in the late 18th century, however, when English and American Quakers began to question the