Considering the changes in moral principles, human behavior and behavioral values through the ages, in Egill Skallagrimsson's Saga, Egill presents us with altered mental status. This is in terms of what at present is considered symptoms of an anti-social personality, and bipolar affective disorder. Egill Skallagrimsson is considered one of the most famous Vikings in the Icelandic Sagas. Archaeological findings mentioned in Egill's Saga indicate disfigurement of his skull, which has led many authors to suggest that Egill suffered from skeletal dysplasia. The primary assumption in the literature is that Egill Skallagrimsson was affected by Paget's disease of bone. This consideration is additionally based on the scholar's interpretation of the Saga text. The unique storytelling style in the Saga of Egill Skallagrimsson is evident; however, the question of the story's truthfulness remains open. In this article, we investigate Egill Skallagrimsson's assumed Paget's disease of bone, based on the physical and mental symptoms disclosed in the Saga of Egill Skallagrimsson. Associated with the assumption, the author's hermeneutics of Egill's Saga in the context of modern-day knowledge of Paget's disease of bone, brings forward the probability estimate to the range of permille. In Scandinavian folklore and mythology, a tale by Saxo Grammaticus of a notorious shield-maiden named Visna, reminds of Egill, as noted by Snorri Sturluson. Hence, in reference to Egill Skallagrimsson's mental status and physical appearance as listed in Egill's Saga, the authors recommend the name for his condition to be "Visna of Egill Skallagrimsson".
Keywords: Egill Skallagrimsson; Paget‘s disease of bone; bipolar affective disorder; dementia; hydrocephalus; skeletal dysplasia.