The principal sources on illness in historic periods can be divided into "intrinsic" medical practice, further ideas and conceptions about disease. Legal texts, in the form of laws and verdicts, represent interesting cues. Popular and folklore traditions comprise important and challenging sources, and not least, fictional literature from Homer to the present day gives us important information about the practice, ideas and social implications of psychiatric disorders. In the Viking Age (800-1030 a.d.) and the Middle Ages (1030-1500 a.d.) in Northern Europe, the main available information stems from fictional literature - more precisely the sagas, written predominantly in Iceland during the 13th century: Above all, the Kings' sagas of Snorri Sturlusson and the Icelandic family sagas give short remarks and anecdotes as well as more extensive and perspicuous narratives. On the whole, these "reports" reveal an almost "clinical" descriptive and rationalistic ideal, giving insight into attitudes and reactions to psychiatric illness. Considered according to present day's categorization, the described psychopathological spectrum covers three main areas: 1) affective disorders caused by loss and mourning (sometimes with psychotic symptoms); 2) acute ("reactive") psychoses; 3) dissociative disorders (berserkr). Oligophrenia (or pervasive developmental disorders) as well as bipolar syndromes might be suspected from a few accounts. Some vague notions on aetiology of psychiatric ills are reflected in these texts, for example on the role of heredity. Some kind of basic understanding of the importance of psychological loss prevails in the frequent descriptions of depressive reactions. Overall, the accounts seem largely non-theoretical, uninfluenced by contemporary medical theories.