Aside from the Tritons, benevolent Greco-Roman divinities, no other anthropomorphic monster was located in the Mediterranean during Antiquity. The situation, however, is very different for the Northern seas in the Middle Ages. Indeed, this category of hybrid appears there with a little more frequency, and is both more diversified and increasingly ambivalent in meaning. The positive connotations these beings carry sometimes seem directly tied to their original or adoptive culture, contrary to their negative connotations, which resulted from the demonizing process directed at monsters by the Catholic Church. The present paper will briefly sketch out this rather particular category of marine creatures, will provide details on the context in which it develops and will attempt to explain the reasons for its extraordinary popularity, as much in the domain of the written word as in art and even heraldry. Thus, the paper will deal with a cultural imaginary dominated by the sea and imbued with the belief in a marine world exactly parallel with the terrestrial world, as well as the particular history of each of the marine hybrids, whether they originate in Antiquity or are from their beginning anchored in Northern cultures. We will show then that whatever might be the case, these Northern seas have played a determining role in the elaboration and/or the evolution of the idea of marine hybrids, and, indeed, even their form. We will conclude by asking why mermen and merwomen ended up by becoming a sort of leitmotif in the illustration of certain great works of natural history at the end of the Middle Ages even though the textual tradition of these creatures presents them within a quite different morphology.
Sea monsters, sea world, Middle Ages, siren, mermaid, merman.