Mary Slessor's primary concern was to eliminate the tribal superstitious practice of killing twin babies in Calabar, Nigeria. She was a Scottish Presbyterian who worked as a missionary in Calabar during the late 19th and early 20th century. She learned the Efik language and culture, and with the support of the local chiefs, she worked to stop the killing of twin babies, who were believed to be evil spirits. She also adopted many of the children who were abandoned due to this belief, and raised them as her own. Mary Slessor is remembered today for her humanitarian work, and for her efforts to promote the rights of women and children in Nigeria.