[5] The society, economy, settlement and culture of the territory of what is in the present-day the country of Estonia is studied mainly through archaeological sources.

The overall understanding of the Viking Age in Estonia is deemed to be fragmentary and superficial, because of the limited amount of surviving source material.

The main sources for understanding the period are remains of the farms and fortresses of the era, cemeteries and a large amount of excavated objects.

[7] There were a number of late prehistoric or medieval harbour sites on the coast of Saaremaa, but none have been found that are large enough to be international trade centres.

[8] Saxo Grammaticus describes the inhabitants of Estonia and the Curonians as participating in the Battle of Bråvalla on the side of the Swedes against the Danes, who were aided by the Livonians and the Wends of Pomerania.

[9] Snorri Sturluson relates in his Ynglinga saga how the Swedish king Ingvar Harra (7th century), the son of Östen and a great warrior, who was forced to patrol the shores of his kingdom fighting pirates from Estonia.

[10] According to Heimskringla sagas, in the year 967 the Norwegian Queen Astrid escaped with her son, later king of Norway Olaf Tryggvason, from her homeland to Novgorod where her brother Sigurd held an honoured position at the court of Prince Vladimir.

Six years later, when Sigurd Eirikson traveled to Estonia to collect taxes on behalf of Valdemar, he spotted Olaf in a market on Saaremaa and paid for his freedom.

[citation needed] A battle between Estonian and Icelandic Vikings off Saaremaa is described in Njál's saga as occurring in 972 AD.

The local inhabitants, taken by surprise, had at first tried to negotiate the demands made by the king and his men, but then gathered an army and confronted them.

According to historical rhymed sources:"Deluded by their bravery / They went through all the land [...] / All paths, and also tracks / Were covered rich in blood [...] / They taught folk how to die / Both men and women / If only they have failed to flee.

[7] The ship burials at Salme that were excavated in 2011 and 2013, and have been dated to circa 750 AD, have been interpreted as being of men who had travelled to Saaremaa from Sweden, based on all weapons and other artefacts being of typically Swedish types, but excavations of a cult site at Viidumäe on Saaremaa (20 km from Salme), beginning in 2014, a site dated to the 7th and 8th centuries, that is before and slightly after the Salme ship burials, have shed new light on that, since a large number of weapons and other items of the same types as those found at Salme have been found at the cult site, in a clearly local context with a large number of dress pins of local type but with typical Scandinavian decorations, showing the same types of weapons were in local use.

Archaeologist Andres Tvauri has commented on the question of ethnicities: I am convinced that the contemporary Estonian national identity is a product of the events and ideologies of the 18th–19th centuries.

[7] Northern and Western Estonia matched, in general, the areas of the historical provinces Saaremaa, Läänemaa, Harjumaa and Virumaa.

[citation needed] The local tribes were eventually overwhelmed and underwent baptism, military occupation and sometimes extermination by German, Danish and Swedish forces.