When was Joanna Vassa's father's autobiography published?
Joanna Vassa: Joanna Vassa (1795-1857) was the only surviving child of the former slave and anti-slavery campaigner Olaudah Equiano. Olaudah Equiano:  His autobiography, published in 1789, helped in the creation of the Slave Trade Act 1807 which ended the African trade for Britain and its colonies.
1789