What kind of being did a sailor see, when he was confronted with a mermaid? A demon, a fairy, a monster, or only an extraordinary marine mammal? Transmitted by the tradition of ancient natural history the European universities faced many creatures belonging to natural science as well as to mythology, which still could be observed throughout the world. While medieval sholarship treated those beings as subjects for demonology, early modern scholars started to rationalize the sirens and satyrs and developed new models of explanation. Throughout hundreds of academical disputations the debate on...