Beings that come from the past into the present could be an example par excellence for memory studies. Revenants are an outstanding phenomenon of Old Norse literature that has been researched from many points of view: e.g. those of literary science, historical sociology, anthropology and history of religion. Their results are completely different as they ask different questions. In the first part of the article, statements about Old Norse revenants are ordered according to which of four Aristotle’s causes they relate. Then, revenants are framed in the context of memory studies. It might offer a modest perspective, concentrating on memory, i.e. the context the story is set into. From that point of view, we can see a dialogue with a past version of a person, with what he brought to the world and what he left there, i.e. with memory. As it is mostly a disturbing past that revenants represent, they can be seen as literally embodying a problem that lies in (individual or cultural) memory. Within the saga genres, an important difference consists in whether the past (revenants) haunts a man or a hero actively seeks the past.