Angels on horseback are oysters wrapped in bacon. They can be served on toast or other breads, as a canapé.
According to Wikipedia, devils on horseback are "bacon–wrapped dried fruit stuffed with various ingredients like cheese and nuts wrapped in bacon or similar pork like prosciutto or pancetta." Wikipedia adds that "the traditional form of the dish is made with a pitted prune, but dates are also used, usually steeped in brandy or some other liqueur."
Wikipedia suggests that both items are Victorian in origin. Many sources give Mrs. Beeton's Book of Household Management (1888) as the first appearance in print of angels on horseback, but Wikipedia claims that they were mentioned in an Australian newspaper six years earlier.
© Haydn Thompson 2018