Joseph Kasa-Vubu was born in the village of Kuma-Dizi in the Mayombe district of the Belgian Congo. Different sources list his year of birth as 1910, 1913, 1915, or 1917, though 1915 is the most probable date. He was the eighth of nine children in a family of the Yomba ethnic group, a subset of the Kongo people. His father was a successful farmer who, as an independent entrepreneur, traded with street merchants in Cabinda and built his house at the outskirts of the village. This earned him the animosity of the villagers and in an attempt to assuage their hostility he volunteered to undergo a "poison test" with a substance extracted from a kasa tree. The word "Kasa" was appended onto his name in commemoration of the event. Kasa-Vubu's mother died four years after his birth, and his father died in 1936. On 31 January 1925 he was baptised under the Christian name of Joseph at the Scheutist Catholic mission of Kizu, near Tshela.