Old Prussians
According to a legend, recorded by Simon Grunau, the name "Prussia" is derived from Pruteno (or Bruteno), the chief priest of Prussia and brother of the legendary king Widewuto, who lived in the 6th century. The regions of Prussia and the corresponding tribes are said to bear the names of Widewuto's sons — for example, Sudovia is named after Widewuto's son Sudo. In the first half of the 13th century, Bishop Christian of Prussia recorded the history of a much earlier era. Adam of Bremen mentions Prussians in 1072.
The Old Prussians spoke a variety of languages, with Old Prussian belonging to the Western branch of the Baltic language group. Related, but not mutually intelligible, are the modern representatives of the Baltic languages: Latvian and Lithuanian, from the East Baltic branch. Roman historians had documented the Prussian tribes as easterners, with Tacitus' referring to them as the Aesti.
The territory was identified as Brus in the 8th century map of the Bavarian geographer
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