According to archaeological finds, the territory of Saaremaa has been inhabited for at least 5,000 years. Sagas talk about numerous skirmishes between islanders and Vikings. Saaremaa was the wealthiest county of ancient Estonia and the home of notorious Estonian pirates, sometimes called the Eastern Vikings. The Chronicle of Henry of Livonia describes a fleet of sixteen ships and five hundred Osilians ravaging the area that is now southern Sweden, then belonging to Denmark. In 1206, King Valdemar II of Denmark built a fortress on the island but found no volunteers to man it. The Danes burned it themselves and left.
Probably around 1000 Gunnar Hámundarson from Iceland was in wiking at Eysýsla (Saaremaa). There he obtained his famous atgeir, by taking it from a man named Hallgrímur. Njáls saga tells the following:
"Thence they held on south to Denmark and thence east to Smálönd and had victory wherever they went. They did not come back in autumn. The next summer they held on to Rafala (Tallinn) and fell in there with sea-rovers, and fought at once, and won the fight. After that they steered east to Eysýsla (Saaremaa) and lay there somewhile under a ness. There they saw a man coming down from the ness above them; Gunnar went on shore to meet the man, and they had a talk. Gunnar asked him his name, and he said it was Tófi. Gunnar asked again what he wanted. "Thee I want to see," says the man. " Two warships lie on the other side under the ness, and I will tell thee who command them: two brothers are the captains -- one's name is Hallgrímur, and the other's Kolskeggur. I know them to be mighty men of war; and I know too that they have such good weapons that the like are not to be had. Hallgrímur has an atgeir which he had made by seething-spells; and this is what the spells say, that no weapon shall give him his death-blow save that atgeir. That thing follows it too that it is known at once when a man is to be slain with that atgeir, for
