The island of Jarise järv lake as can be seen on the map below is coloured dark red. The dark red areas indicate original Viking settlements.
Estland (Eistland or Esthland) is the historical Germanic language name that refers to the country at the eastern shores of the Baltic Sea, and is the origin of the modern national name for Estonia. The largest island of Estonia is called Ösel in Swedish and its inhabitants used to be called Oeselians
The Oeselians were known in the Old Norse Icelandic Sagas and in Heimskringla as Víkingr frá Esthland (English: vikings from Estonia).
The history of the vikings of Estonia is a remarkable one if one is till to consider (I am not) to pinpoint 'The Viking Age' between 793 A.D. and 1066 A.D. - as that addresses a British actuality, certainly not the actuality all over the Viking world.
Around 850 A.D. Estonia was on the southeastern trading route of the Vikings to the Black Sea and Turkey onwards. In the following centuries Slavic tribes from Russia failed to submit the citizenry and missionaires from Denmark, Sweden and Germany failed either attempting to christianize the people. In 1093 A.D. the pope even sent crusaders to the area. Around 1187 A.D. (!) vikings from Estonia plundered Swedish towns, but finally in 1227 A.D. German knights succeeded, after more than 25 years of resistance of the Estsled by Lembitu, to get control on large parts of the coastal areas.