Pots in which twin babies were exposed to die, c1880. In August 1888, Mary Slessor lived with the Okoyong and the Efik people of Nigeria. It was the belief in the area that the birth of twins was considered a particularly evil curse. They often abandoned both babies in clay pots to die. Mary Mitchell Slessor (2 December 1848 - 13 January 1915) was a Scottish Presbyterian missionary to Nigeria. Because of her understanding of the native language and her bold personality Slessor gained the trust and acceptance of the locals and was able to spread Christianity while promoting women's rights and protecting native children