The island of Tanna holds the two movements most often cited in outside writing about Melanesian religion, and both are routinely misdescribed.
The John Frum movement emerged around 1940, when Presbyterian mission discipline on Tanna was at its most restrictive, banning dancing, kava and much of kastom. A figure called John Frum was said to have appeared and to have told Tannese to abandon the mission and the colonial economy and return to their own practice. Adherents left the mission stations, threw away colonial currency and resumed kava and dancing, and the condominium authorities imprisoned leaders. The arrival of very large quantities of American materiel and of Black American servicemen during the Pacific war was then read into the movement, and its adherents mark 15 February each year with drilling, uniforms and a raised American flag.
The category cargo cult, applied to this from the outside, is now largely rejected by anthropologists, and for good reasons. The movement was in the first place a rejection of mission authority and an assertion of kastom, not a technique for obtaining goods; the wealth it concerned was understood in terms of relationship and reciprocity, which is how wealth works in Melanesian exchange generally; and the label bundled together very different movements while making their adherents look foolish.
The Prince Philip Movement, in villages in the south of Tanna, identified the Duke of Edinburgh as a Tannese spirit who had travelled overseas and married a powerful woman, a reading consistent with local narratives about a pale skinned son of a mountain spirit. Adherents corresponded with him, exchanged gifts and photographs over decades, and mourned him formally on his death in 2021.