William Napoleon Barleycorn (1848–1925), born in Santa Isabel, Fernando Po, Spanish Guinea and a Krio Fernandino of Igbo descent,[1] was a Primitive Methodist missionary who went to Fernando Po (now known as Bioko) in Africa in the early 1880s.

[2] During the early 1870s, William Barleycorn was a Sunday school teacher, a member of the Native Missionary Class, and a preacher at the local Bubi village of Basupu.

In 1871 he abandoned running a small trading store and moved to San Carlos (North-West Bay) to work as an assistant for a European missionary.

In 1884 he became listed as one of the regular ministers, and studied in Barcelona for two years to obtain his Spanish teaching certificate.

He became the visible leader of Santa Isabel's Fernandino community by the 1890s, and served as a patriarchal remnant of the Anglophone and Protestant influence on the island.